Building a shed from scratch

Discussion in 'Misc DIY' started by Steven Briggs, Apr 9, 2004.

  1. Hello all.

    This years project looks set to be a large shed at mums place.

    I'll be building from scratch, as I want a challenge and to achieve
    something better, more substantial and different from the usual stuff.

    It'll be about 18' x 8', part potting shed, part summer house, with
    covered veranda deck area. There's a CAD render of the design at
    <http://www.sbriggs.plus.com/shed14.jpg>

    I have a few questions for the collective wisdom of the group on
    construction methods and materials.


    The latest thinking on the base is to mount it on single brick pads (on
    a large, existing concrete platform), then a 50x100 joist frame, T&G
    floor, then the shed structure.

    Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,
    50x75 sill & head. Inside skinned with 6mm WBP ply, outside with VT&G
    weatherboard. I'll put about 30mm of Celotex / Kingspan on the inside
    face of the wall cavity. I'm debating the need to vent the remaining
    cavity to the outside, I can easily have a 10mm hidden gap around the
    framing at ground & eaves level, and over the roof ridge board. Is this
    a good idea? Should I put a vapour barrier in there somewhere? If so,
    what to use?

    Timber treatment is another issue. While the floor joists will be
    tanalised timber, I don't think my local timber yard has on-site
    treatment plant, so everything else (weatherboarding, frame, floor etc)
    will be untreated red or white wood. I could then paint or spray a
    suitable preservative on, but would it really be worth shopping round
    and getting the whole lot prevac treated (which adds about 20% to the
    cost)?

    Any other construction or material suggestions welcome.

    Finally, this is grand excuse for compressor and nail gun purchase.
    Probably the Axminster £100 compressor (2.5HP /25L /7cfm FAD) and 50mm
    brad nailer. Are 18ga brads going to adequate for the cladding?


    Cheers all,

    --
    Steve
     
    Steven Briggs, Apr 9, 2004
    #1
    1. Advertising

  2. Steven Briggs

    Andy Hall Guest

    On Fri, 9 Apr 2004 20:54:21 +0100, Steven Briggs
    <> wrote:

    >Hello all.
    >
    >This years project looks set to be a large shed at mums place.
    >
    >I'll be building from scratch, as I want a challenge and to achieve
    >something better, more substantial and different from the usual stuff.
    >
    >It'll be about 18' x 8', part potting shed, part summer house, with
    >covered veranda deck area. There's a CAD render of the design at
    ><http://www.sbriggs.plus.com/shed14.jpg>
    >


    Nice design - I think she should be very pleased.


    >I have a few questions for the collective wisdom of the group on
    >construction methods and materials.
    >
    >
    >The latest thinking on the base is to mount it on single brick pads (on
    >a large, existing concrete platform), then a 50x100 joist frame, T&G
    >floor, then the shed structure.


    With this, I wouldn't go for more than 450mm centres.

    You will need a matrix of brick piers.

    Alternatively, what I did was to start with a concrete base and then
    use pressure treated wooden bearers on it and the joists orthogonally
    on top of that. It's worth putting some DPC material like Visqueen
    down to isolate the timbers from the concrete. You can also use
    packing pieces on top of the bearers in order to level the final
    floor.


    >
    >Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,


    I'd up that to 50x75mm for good strength.

    >50x75 sill & head. Inside skinned with 6mm WBP ply,


    I would go for 12mm or even 18mm there because you can fix things to
    it. 18mm ply is used in large quantities (or OSB as an alternative)
    so it is not that expensive. You will get a much sturdier result.


    >outside with VT&G
    >weatherboard.


    That's fine.

    > I'll put about 30mm of Celotex / Kingspan on the inside
    >face of the wall cavity. I'm debating the need to vent the remaining
    >cavity to the outside, I can easily have a 10mm hidden gap around the
    >framing at ground & eaves level, and over the roof ridge board. Is this
    >a good idea?


    Yes. What I did was to tack nail small spacers to the sides of the
    vertical studs such that the Celotex front face was level with the
    front of the studs. Then I tape sealed the Celotex to the studs with
    metallised tape and ply clad on top of that. This created an air
    gap behind and ventilation was arranged to the air gap.


    >Should I put a vapour barrier in there somewhere? If so,
    >what to use?


    Celotex has foil on both sides and you do not need an additional
    vapour barrier.

    It would also be worth insulating the floor and ceiling.

    For the floor, build the floor frame and then tack nail spacers in
    the same way as I described for the walls. Drop in the Celotex and
    put flooring on top of that. I used 18mm T&G for that.

    it is also worth insulating the roof. I used exactly the same
    technique for that, making sure that there is ventilation on the cold
    side.


    >
    >Timber treatment is another issue. While the floor joists will be
    >tanalised timber, I don't think my local timber yard has on-site
    >treatment plant, so everything else (weatherboarding, frame, floor etc)
    >will be untreated red or white wood. I could then paint or spray a
    >suitable preservative on, but would it really be worth shopping round
    >and getting the whole lot prevac treated (which adds about 20% to the
    >cost)?


    I dealt with this by using Cuprinol Clear Wood Preserver. which is a
    spirit based product.

    When you get your compressor, get a cheap air powered paint sprayer
    and then spray both sides of the timbers. Three coats are recommended.
    You can apply any other finish afterwards if you want to.



    >
    >Any other construction or material suggestions welcome.


    Use a very good quality roofing felt. The heavy grade is not a lot
    more than the cheap shed stuff and lasts a lot longer.



    >
    >Finally, this is grand excuse for compressor and nail gun purchase.
    >Probably the Axminster £100 compressor (2.5HP /25L /7cfm FAD) and 50mm
    >brad nailer. Are 18ga brads going to adequate for the cladding?


    Not really. I used 16 gauge. 18 gauge is normally used to hold
    things together for gluing, not for fixing. You need a nailer that
    takes 16ga finish nails.


    >
    >
    >Cheers all,


    ..andy

    To email, substitute .nospam with .gl
     
    Andy Hall, Apr 9, 2004
    #2
    1. Advertising

  3. In message <>, Andy Hall
    <> writes
    >On Fri, 9 Apr 2004 20:54:21 +0100, Steven Briggs
    ><> wrote:
    >
    >>Hello all.
    >>
    >>This years project looks set to be a large shed at mums place.
    >>
    >>I'll be building from scratch, as I want a challenge and to achieve
    >>something better, more substantial and different from the usual stuff.
    >>
    >>It'll be about 18' x 8', part potting shed, part summer house, with
    >>covered veranda deck area. There's a CAD render of the design at
    >><http://www.sbriggs.plus.com/shed14.jpg>
    >>

    >
    >Nice design - I think she should be very pleased.
    >
    >
    >>I have a few questions for the collective wisdom of the group on
    >>construction methods and materials.
    >>
    >>
    >>The latest thinking on the base is to mount it on single brick pads (on
    >>a large, existing concrete platform), then a 50x100 joist frame, T&G
    >>floor, then the shed structure.

    >
    >With this, I wouldn't go for more than 450mm centres.
    >
    >You will need a matrix of brick piers.
    >

    That is the plan.

    >Alternatively, what I did was to start with a concrete base and then
    >use pressure treated wooden bearers on it and the joists orthogonally
    >on top of that. It's worth putting some DPC material like Visqueen
    >down to isolate the timbers from the concrete. You can also use
    >packing pieces on top of the bearers in order to level the final
    >floor.
    >
    >
    >>
    >>Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,

    >
    >I'd up that to 50x75mm for good strength.
    >
    >>50x75 sill & head. Inside skinned with 6mm WBP ply,

    >
    >I would go for 12mm or even 18mm there because you can fix things to
    >it. 18mm ply is used in large quantities (or OSB as an alternative)
    >so it is not that expensive. You will get a much sturdier result.
    >
    >
    >>outside with VT&G
    >>weatherboard.

    >
    >That's fine.
    >
    >> I'll put about 30mm of Celotex / Kingspan on the inside
    >>face of the wall cavity. I'm debating the need to vent the remaining
    >>cavity to the outside, I can easily have a 10mm hidden gap around the
    >>framing at ground & eaves level, and over the roof ridge board. Is this
    >>a good idea?

    >
    >Yes. What I did was to tack nail small spacers to the sides of the
    >vertical studs such that the Celotex front face was level with the
    >front of the studs. Then I tape sealed the Celotex to the studs with
    >metallised tape and ply clad on top of that. This created an air
    >gap behind and ventilation was arranged to the air gap.
    >

    Ah, good idea.

    >It would also be worth insulating the floor and ceiling.


    They will be.
    >
    >For the floor, build the floor frame and then tack nail spacers in
    >the same way as I described for the walls. Drop in the Celotex and
    >put flooring on top of that. I used 18mm T&G for that.
    >
    >it is also worth insulating the roof. I used exactly the same
    >technique for that, making sure that there is ventilation on the cold
    >side.
    >

    Yep. Ventilation from eaves, and a small gap over the top of the ridge
    board.

    >
    >>
    >>Finally, this is grand excuse for compressor and nail gun purchase.
    >>Probably the Axminster £100 compressor (2.5HP /25L /7cfm FAD) and 50mm
    >>brad nailer. Are 18ga brads going to adequate for the cladding?

    >
    >Not really. I used 16 gauge. 18 gauge is normally used to hold
    >things together for gluing, not for fixing. You need a nailer that
    >takes 16ga finish nails.
    >
    >

    Yeah, I thought it a little mean for the job too. But 16ga nailers are
    way more expensive (£175 vs £45). I'll have to see what's in the piggy
    bank.

    Thanks Andy.

    Now back to the CAD drawing. Doing a detailed frame design now. Next
    challenge is to draw the valley rafters.

    <http://www.sbriggs.plus.com/shedv305.jpg>

    is this afternoons efforts.
    --
    Steve
     
    Steven Briggs, Apr 9, 2004
    #3
  4. Steven Briggs

    Andy Hall Guest

    On Fri, 9 Apr 2004 21:58:31 +0100, Steven Briggs
    <> wrote:

    >
    >>>
    >>>The latest thinking on the base is to mount it on single brick pads (on
    >>>a large, existing concrete platform), then a 50x100 joist frame, T&G
    >>>floor, then the shed structure.

    >>
    >>With this, I wouldn't go for more than 450mm centres.
    >>
    >>You will need a matrix of brick piers.
    >>

    >That is the plan.


    OK. For this, I wouldn't go for a distance between piers of more
    than a metre, otherwise the floor is going to be very bouncy.

    That's going to be a lot of piers (around 15-20). If the existing
    base is reasonable, I would rethink the timber bearers idea.

    Also, it's useful to make a complete frame with the floor joists with
    timbers across the ends. Then you can make a skirt of TGV cladding
    and take it almost to the concrete.

    >
    >>Alternatively, what I did was to start with a concrete base and then
    >>use pressure treated wooden bearers on it and the joists orthogonally
    >>on top of that. It's worth putting some DPC material like Visqueen
    >>down to isolate the timbers from the concrete. You can also use
    >>packing pieces on top of the bearers in order to level the final
    >>floor.
    >>
    >>
    >>>
    >>>Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,

    >>
    >>I'd up that to 50x75mm for good strength.
    >>
    >>>50x75 sill & head. Inside skinned with 6mm WBP ply,

    >>
    >>I would go for 12mm or even 18mm there because you can fix things to
    >>it. 18mm ply is used in large quantities (or OSB as an alternative)
    >>so it is not that expensive. You will get a much sturdier result.
    >>
    >>
    >>>outside with VT&G
    >>>weatherboard.

    >>
    >>That's fine.
    >>
    >>> I'll put about 30mm of Celotex / Kingspan on the inside
    >>>face of the wall cavity. I'm debating the need to vent the remaining
    >>>cavity to the outside, I can easily have a 10mm hidden gap around the
    >>>framing at ground & eaves level, and over the roof ridge board. Is this
    >>>a good idea?

    >>
    >>Yes. What I did was to tack nail small spacers to the sides of the
    >>vertical studs such that the Celotex front face was level with the
    >>front of the studs. Then I tape sealed the Celotex to the studs with
    >>metallised tape and ply clad on top of that. This created an air
    >>gap behind and ventilation was arranged to the air gap.
    >>

    >Ah, good idea.
    >
    >>It would also be worth insulating the floor and ceiling.

    >
    >They will be.


    You might want to think about two glass panels for the windows and
    doors or even find an inexpensive source of double glazing inserts.

    This will make a big difference. With single sheet glass you are
    going to lose a lot of heat. Another option might be secondary
    double glazing inside.


    >>
    >>For the floor, build the floor frame and then tack nail spacers in
    >>the same way as I described for the walls. Drop in the Celotex and
    >>put flooring on top of that. I used 18mm T&G for that.
    >>
    >>it is also worth insulating the roof. I used exactly the same
    >>technique for that, making sure that there is ventilation on the cold
    >>side.
    >>

    >Yep. Ventilation from eaves, and a small gap over the top of the ridge
    >board.
    >

    I made a ridge cap out of Western Red Cedar and spaced it off from
    the roof. There were ventilation strips set into the top of the
    ridge underneath the cap.

    This means that air is drawn in under the eaves into the space above
    the insulation and out at the ridge.



    >>
    >>>
    >>>Finally, this is grand excuse for compressor and nail gun purchase.
    >>>Probably the Axminster £100 compressor (2.5HP /25L /7cfm FAD) and 50mm
    >>>brad nailer. Are 18ga brads going to adequate for the cladding?

    >>
    >>Not really. I used 16 gauge. 18 gauge is normally used to hold
    >>things together for gluing, not for fixing. You need a nailer that
    >>takes 16ga finish nails.
    >>
    >>

    >Yeah, I thought it a little mean for the job too. But 16ga nailers are
    >way more expensive (£175 vs £45). I'll have to see what's in the piggy
    >bank.


    18 ga really is not going to do a good job of holding the boards.

    The time saving of a nailer on a job like this is enormous so it is
    worth the investment.

    Rutlands (www.rutlands.co.uk) have a 16ga nailer for £150.

    Top Gun Air Nailers (www.topgun.co.uk) have a Porter Cable for £150
    plus VAT (£176).
    I have several Porter Cable nailers of different sizes including this
    one. Porter Cable and Senco are the two leading makes and this is a
    good deal.

    I have also found Top Gun to be really good and helpful on obtaining
    nails at pretty good prices.

    For example, I used cedar shakes for the roof of the cabin that I
    built last year.

    http://www.johnbrash.co.uk/shakes.shtml

    These cannot be fixed with galvanised nails because the tannin in the
    cedar corrodes them, so stainless steel was needed. Not easy to get
    but Top Gun managed to source and supply some.

    >
    >Thanks Andy.
    >
    >Now back to the CAD drawing. Doing a detailed frame design now. Next
    >challenge is to draw the valley rafters.
    >
    ><http://www.sbriggs.plus.com/shedv305.jpg>
    >
    >is this afternoons efforts.



    If you need some help in the detail of the studs and rafters, there is
    a good plan for the construction of a shed at

    http://www.plansnow.com/shed.html which can be downloaded for $9.50.

    This uses more or less exactly the construction that you have
    described and goes into how to correctly joint and notch the framing.





    ..andy

    To email, substitute .nospam with .gl
     
    Andy Hall, Apr 9, 2004
    #4
  5. Steven Briggs

    John Rumm Guest

    Steven Briggs wrote:

    > I'll be building from scratch, as I want a challenge and to achieve
    > something better, more substantial and different from the usual stuff.


    That sounds familiar - played the same game myself a couple of years ago...

    > It'll be about 18' x 8', part potting shed, part summer house, with
    > covered veranda deck area. There's a CAD render of the design at
    > <http://www.sbriggs.plus.com/shed14.jpg>


    Oh very posh ;-) Mine was a bit simpler:-

    http://www.internode.ltd.uk/workshop/plans.htm

    > I have a few questions for the collective wisdom of the group on
    > construction methods and materials.


    Fire away...

    > The latest thinking on the base is to mount it on single brick pads (on
    > a large, existing concrete platform), then a 50x100 joist frame, T&G
    > floor, then the shed structure.


    I did similar - 50x100 floor beams at about 500mm centres on a matrix of
    half bricks set level on the concrete base. I used 19mm ply for the
    floor which worked very well.

    > Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,


    50x75 for the framing will give a really solid frame and a bit more
    space to play with for insulating and adding electrics etc if required.

    > 50x75 sill & head. Inside skinned with 6mm WBP ply, outside with VT&G


    50x100 ridge beam, 19mm shiplap cladding, 12mm WBP ply on the inside -
    as Andy suggests it is nice and easy to fix things to after.

    > weatherboard. I'll put about 30mm of Celotex / Kingspan on the inside
    > face of the wall cavity. I'm debating the need to vent the remaining
    > cavity to the outside, I can easily have a 10mm hidden gap around the
    > framing at ground & eaves level, and over the roof ridge board. Is this
    > a good idea? Should I put a vapour barrier in there somewhere? If so,
    > what to use?


    Not suggesting this is the best way - but I went for 50mm jabfloor
    (cheaper than celotex - but not quite as good - so your 30mm will
    probably be as good or better). I fitted it flush with the outside of
    the framing so that it formed a vapour barrier next to the shiplap -
    that then left 25mm of space inside the warm/dry area for all the
    electrics I wanted installed in/under the interior ply.

    > Timber treatment is another issue. While the floor joists will be
    > tanalised timber, I don't think my local timber yard has on-site
    > treatment plant, so everything else (weatherboarding, frame, floor etc)
    > will be untreated red or white wood. I could then paint or spray a
    > suitable preservative on, but would it really be worth shopping round
    > and getting the whole lot prevac treated (which adds about 20% to the
    > cost)?


    Bog standard sawn kiln dried timber is nicer to work with and cheaper -
    just give it a few good coats of cuprinol first.

    (as an aside, using a low pressure "pump up" sprayer is a quick way of
    doing the job without loosing as much cuprinol as you will with the
    finer atomisation you get with a spray gun on the compressor - really it
    needs soaking more than it needs a fine finish. I originally did my one
    with a brush which took ages - got a pump up sprayer from Wicks the
    other day for about 13 quid, that let me re-spray the whole thing in
    about an hour)

    > Any other construction or material suggestions welcome.


    In no particular order:

    Good three layers of felt on top of at least 12mm WBP ply.

    Leave a little air gap underneath the whole shed so that it stays
    ventilated.

    Give the floor beams and the underside of the floor a good soaking in
    wood preserver since you will not be seeing them again for a long time.

    Get a decent respirator if spraying cuprinol (the 15 quid 3M jobbies
    from Screwfix work well and will also block the smell of the stuff
    completely)

    Stick some diagonal cross braces in the wall stud work as it will make
    the whole thing much more rigid and will prevent any of the framing
    leaning or skewing. I ended up using only half the amount that you see
    on the drawings - as that seemed to be enough - but doing some is well
    worth it. While on the topic, stick a couple of cross braces between
    some of the rafters - this will convert the load of the roof (and anyone
    on it!) into a downward thrust rather than a "splaying" thrust that
    would otherwise tend to push the walls out. Note also three layers of
    roofing felt is heavy!

    > Finally, this is grand excuse for compressor and nail gun purchase.
    > Probably the Axminster £100 compressor (2.5HP /25L /7cfm FAD) and 50mm
    > brad nailer. Are 18ga brads going to adequate for the cladding?


    My tools / materials shopping list was:-

    http://www.internode.ltd.uk/workshop/tips.htm

    18g are a bit on the light side - having said that - they are what I
    used. I used 30mm brads which are cheap enough you can afford to use
    loads. Hence I stuck between three and five into the lower quarter of
    each plank every time it crossed a joist. It has been up a couple of
    years now and seems to be holding tight - although it is in a reasonably
    sheltered location.

    Anyway if you want the whole saga you can read it here:-

    http://www.internode.ltd.uk/workshop/


    --
    Cheers,

    John.

    /=================================================================\
    | Internode Ltd - http://www.internode.co.uk |
    |-----------------------------------------------------------------|
    | John Rumm - john(at)internode(dot)co(dot)uk |
    \=================================================================/
     
    John Rumm, Apr 10, 2004
    #5
  6. In message <AQHdc.31476$Y%9.net>, John Rumm
    <> writes
    >Steven Briggs wrote:
    >> Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,

    >
    >50x75 for the framing will give a really solid frame and a bit more
    >space to play with for insulating and adding electrics etc if required.
    >


    I've just been down the timber yard, sawn 25x75 is a bit scaggy. 2nd
    choice was CLS, but they only have 2.4m in stock. So 50x75 regularised
    carcassing it is. It'll work out the same cost as CLS when wastage is
    taken in to account.

    >> 50x75 sill & head. Inside skinned with 6mm WBP ply, outside with VT&G

    >
    >50x100 ridge beam, 19mm shiplap cladding, 12mm WBP ply on the inside -
    >as Andy suggests it is nice and easy to fix things to after.
    >

    I think if it were my shed, I'd use 12mm, but I don't think there'll be
    much, if anything, hung of the walls in this case. 6mm is much easier to
    handle single-handed too.

    >> weatherboard. I'll put about 30mm of Celotex / Kingspan on the inside
    >>face of the wall cavity. I'm debating the need to vent the remaining
    >>cavity to the outside, I can easily have a 10mm hidden gap around the
    >>framing at ground & eaves level, and over the roof ridge board. Is
    >>this a good idea? Should I put a vapour barrier in there somewhere?
    >>If so, what to use?

    >
    >Not suggesting this is the best way - but I went for 50mm jabfloor
    >(cheaper than celotex - but not quite as good - so your 30mm will
    >probably be as good or better). I fitted it flush with the outside of
    >the framing so that it formed a vapour barrier next to the shiplap -
    >that then left 25mm of space inside the warm/dry area for all the
    >electrics I wanted installed in/under the interior ply.
    >


    I thought Jabfloor was polystrene, i.e. not to be in contact with PVC
    wiring?


    >Stick some diagonal cross braces in the wall stud work as it will make
    >the whole thing much more rigid and will prevent any of the framing
    >leaning or skewing. I ended up using only half the amount that you see
    >on the drawings - as that seemed to be enough - but doing some is well
    >worth it. While on the topic, stick a couple of cross braces between
    >some of the rafters - this will convert the load of the roof (and
    >anyone on it!) into a downward thrust rather than a "splaying" thrust
    >that would otherwise tend to push the walls out. Note also three layers
    >of roofing felt is heavy!
    >

    Good tip, I hadn't thought of diagonals, but it will make a huge
    difference. There's already a divider wall that'll brace the side walls,
    and I was thinking of another one or two cross braces as well.


    >Anyway if you want the whole saga you can read it here:-
    >
    >http://www.internode.ltd.uk/workshop/
    >


    >

    Thanks John.

    --
    Steve
     
    Steven Briggs, Apr 10, 2004
    #6
  7. Peter Crosland, Apr 10, 2004
    #7
  8. On Sat, 10 Apr 2004 02:07:25 +0100, John Rumm
    <> wrote:

    >Anyway if you want the whole saga you can read it here:-
    >
    >http://www.internode.ltd.uk/workshop/


    Excellent! I am reading the whole thing. I especially like the bit
    "...we can see that the drains must have been leaking for a while....
    not to mention a crack in the soil pipe....", as that is pretty much
    what happened to me when I lifted *my* chunk of concrete aka patio! I
    replaced the elbow (clayware) and had to pop down to Tesco's for
    Number Twos for a couple of days while the cement set. (No way would I
    use the public bogs in the village!)

    MM
     
    Mike Mitchell, Apr 10, 2004
    #8
  9. Steven Briggs

    Andy Hall Guest

    On Sat, 10 Apr 2004 11:44:42 +0100, "Peter Crosland"
    <> wrote:

    >Take a look here before you start to make sure you don't run into future
    >problems.
    >
    >http://www.onlineplanningoffices.co.uk/frames.htm
    >




    Which is extremely unlikely.

    Regarding sheds the issues are:

    - Size

    - Proportion of garden covered by all outbuildings and additional
    developments.

    - Height

    - Distance from house. material used may be relevant here.

    - Distance from road


    Unless an absolute monstrosity is constructed, a typical shed or
    summerhouse will not fall foul of any of these.

    It also has to be said that there are large numbers of instances where
    a shed may fail on one or other of these technicalities and the
    planning authority won't bother.

    For example, near me there is an instance where the bottoms of the
    gardens of some houses back onto a road but with normal 2m fencing.
    All of them have at least one shed or greenhouse at the bottom of the
    garden. Technically, these are too close to the road, but it's a
    non-issue to the planners.


    ..andy

    To email, substitute .nospam with .gl
     
    Andy Hall, Apr 10, 2004
    #9
  10. Steven Briggs

    Andy Hall Guest

    On Sat, 10 Apr 2004 11:23:59 +0100, Steven Briggs
    <> wrote:

    >In message <AQHdc.31476$Y%9.net>, John Rumm
    ><> writes
    >>Steven Briggs wrote:
    >>> Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,

    >>
    >>50x75 for the framing will give a really solid frame and a bit more
    >>space to play with for insulating and adding electrics etc if required.
    >>

    >
    >I've just been down the timber yard, sawn 25x75 is a bit scaggy. 2nd
    >choice was CLS, but they only have 2.4m in stock. So 50x75 regularised
    >carcassing it is. It'll work out the same cost as CLS when wastage is
    >taken in to account.


    I was able to get 5.4m delivered by Jewsons if it helps. Pretty
    cheap as I remember. One point is that it is worth going to a place
    like this with your entire shopping list. They will give you a
    project price with quite heavy discounting when you include the
    Celotex and boarding as well.


    >
    >>> 50x75 sill & head. Inside skinned with 6mm WBP ply, outside with VT&G

    >>
    >>50x100 ridge beam, 19mm shiplap cladding, 12mm WBP ply on the inside -
    >>as Andy suggests it is nice and easy to fix things to after.
    >>

    >I think if it were my shed, I'd use 12mm, but I don't think there'll be
    >much, if anything, hung of the walls in this case. 6mm is much easier to
    >handle single-handed too.


    Don't forget that the ply will form part of the strength unless you
    are going to diagonally or cross brace the framing. I think that
    it's better to screw the ply to the frame if you are going to use 6mm.





    >
    >>> weatherboard. I'll put about 30mm of Celotex / Kingspan on the inside
    >>>face of the wall cavity. I'm debating the need to vent the remaining
    >>>cavity to the outside, I can easily have a 10mm hidden gap around the
    >>>framing at ground & eaves level, and over the roof ridge board. Is
    >>>this a good idea? Should I put a vapour barrier in there somewhere?
    >>>If so, what to use?

    >>
    >>Not suggesting this is the best way - but I went for 50mm jabfloor
    >>(cheaper than celotex - but not quite as good - so your 30mm will
    >>probably be as good or better). I fitted it flush with the outside of
    >>the framing so that it formed a vapour barrier next to the shiplap -
    >>that then left 25mm of space inside the warm/dry area for all the
    >>electrics I wanted installed in/under the interior ply.
    >>

    >
    >I thought Jabfloor was polystrene, i.e. not to be in contact with PVC
    >wiring?


    It is.

    For wiring, in any case, I used PVC conduit with singles run in it.
    You can then run additional wiring if you need it later and it's also
    pretty cheap.




    ..andy

    To email, substitute .nospam with .gl
     
    Andy Hall, Apr 10, 2004
    #10
  11. On Sat, 10 Apr 2004 13:07:48 +0100, Andy Hall <>
    wrote:

    >On Sat, 10 Apr 2004 11:44:42 +0100, "Peter Crosland"
    ><> wrote:
    >
    >>Take a look here before you start to make sure you don't run into future
    >>problems.
    >>
    >>http://www.onlineplanningoffices.co.uk/frames.htm
    >>

    >
    >
    >
    >Which is extremely unlikely.
    >
    >Regarding sheds the issues are:
    >
    >- Size
    >
    >- Proportion of garden covered by all outbuildings and additional
    >developments.
    >
    >- Height
    >
    >- Distance from house. material used may be relevant here.
    >
    >- Distance from road
    >
    >
    >Unless an absolute monstrosity is constructed, a typical shed or
    >summerhouse will not fall foul of any of these.
    >
    >It also has to be said that there are large numbers of instances where
    >a shed may fail on one or other of these technicalities and the
    >planning authority won't bother.
    >
    >For example, near me there is an instance where the bottoms of the
    >gardens of some houses back onto a road but with normal 2m fencing.
    >All of them have at least one shed or greenhouse at the bottom of the
    >garden. Technically, these are too close to the road, but it's a
    >non-issue to the planners.
    >
    >

    What about distance from adjoing properties boundaries, if it is wood
    construction over a certain size the minimum distance should be at
    least x m ? Unless of course you have it treated with a flame
    retardant.
     
    David Hemmings, Apr 10, 2004
    #11
  12. Steven Briggs

    Andy Hall Guest

    On Sat, 10 Apr 2004 14:09:36 +0100, David Hemmings
    <> wrote:

    >
    >>

    >What about distance from adjoing properties boundaries, if it is wood
    >construction over a certain size the minimum distance should be at
    >least x m ? Unless of course you have it treated with a flame
    >retardant.



    Basically the rules are this:

    Planning
    ~~~~~~

    Greenhouses & Sheds - (and garages more than 5 metres from the house)
    are permitted if they cover less than 50% and are less than 3m high or
    4m, with a ridge roof.



    Building Control
    ~~~~~~~~~~~

    In order to be exempt the detached building must satisfy the following
    criteria

    No sleeping accommodation
    Internal floor area must not exceed 30m2
    More than 1m from any boundary or substantially non-combustible
    Can be any distance from boundary if not exceeding 15m2 floor area







    ..andy

    To email, substitute .nospam with .gl
     
    Andy Hall, Apr 10, 2004
    #12
  13. Steven Briggs

    John Rumm Guest

    Mike Mitchell wrote:

    > what happened to me when I lifted *my* chunk of concrete aka patio! I
    > replaced the elbow (clayware) and had to pop down to Tesco's for
    > Number Twos for a couple of days while the cement set. (No way would I
    > use the public bogs in the village!)


    I had two solutions to that problem - first: use the plastic collars
    with rubber O rings for joining the pipe - that way as soon as it is
    assembled it is water tight. Second: get the next door neighbours son to
    climb down in the hole and fit the pipe while I promise to not flush the
    loo! ;-)


    --
    Cheers,

    John.

    /=================================================================\
    | Internode Ltd - http://www.internode.co.uk |
    |-----------------------------------------------------------------|
    | John Rumm - john(at)internode(dot)co(dot)uk |
    \=================================================================/
     
    John Rumm, Apr 10, 2004
    #13
  14. Steven Briggs

    John Rumm Guest

    Steven Briggs wrote:

    > I've just been down the timber yard, sawn 25x75 is a bit scaggy. 2nd
    > choice was CLS, but they only have 2.4m in stock. So 50x75 regularised
    > carcassing it is. It'll work out the same cost as CLS when wastage is
    > taken in to account.


    Don't know if your preference for assembly is screwing or nailing, but I
    found that two 4" twinthread quickscreews (Screwfix) per joint made for
    very strong framing even when screwed into the end grain of the wood.

    > I thought Jabfloor was polystrene, i.e. not to be in contact with PVC
    > wiring?


    It is - hence why I put all the wires in oval conduit.

    --
    Cheers,

    John.

    /=================================================================\
    | Internode Ltd - http://www.internode.co.uk |
    |-----------------------------------------------------------------|
    | John Rumm - john(at)internode(dot)co(dot)uk |
    \=================================================================/
     
    John Rumm, Apr 10, 2004
    #14
  15. In message <vcQdc.28837$9.net>, Peter Crosland
    <> writes
    >Take a look here before you start to make sure you don't run into future
    >problems.
    >
    >http://www.onlineplanningoffices.co.uk/frames.htm
    >
    >

    I'm OK for this shed.
    Its in the back garden, well away from the road. The grey block its sat
    upon in the .jpg I linked to is a concrete base of a soon to be
    ex-garage.
    Even measured from the natural grade, I will just be under the 4m height
    limit. Actual height will be about 3.05m from the base level. I don't
    know which level the planners measure from, but I'm OK.


    --
    Steve
     
    Steven Briggs, Apr 10, 2004
    #15
  16. On Sat, 10 Apr 2004 14:19:27 +0100, Andy Hall <>
    wrote:

    >On Sat, 10 Apr 2004 14:09:36 +0100, David Hemmings
    ><> wrote:
    >
    >>
    >>>

    >>What about distance from adjoing properties boundaries, if it is wood
    >>construction over a certain size the minimum distance should be at
    >>least x m ? Unless of course you have it treated with a flame
    >>retardant.

    >
    >
    >Basically the rules are this:
    >
    >Planning
    >~~~~~~
    >
    >Greenhouses & Sheds - (and garages more than 5 metres from the house)
    >are permitted if they cover less than 50% and are less than 3m high or
    >4m, with a ridge roof.
    >
    >
    >
    >Building Control
    >~~~~~~~~~~~
    >
    >In order to be exempt the detached building must satisfy the following
    >criteria
    >
    >No sleeping accommodation
    >Internal floor area must not exceed 30m2
    >More than 1m from any boundary or substantially non-combustible
    >Can be any distance from boundary if not exceeding 15m2 floor area
    >

    Ta, Yes that is what i was on the lines of thinking about.
     
    David Hemmings, Apr 10, 2004
    #16
  17. Steven Briggs

    Pete C Guest

    Hi,

    Nice plans! Might be worth considering 4" rockwool beween 4" joists,
    would be cheaper, better and easier to install than 30mm Celotex I'd
    expect, though a vapour membrane could be necessary.

    If you set the bricks supporting the floor timbers in cement this will
    allow you to even out some variation in the concrete base.

    As far as timber goes, it tends to rot at the ends where exposed to
    water so dipping these pieces in wood preserver then coating the ends
    would be a great help.

    Getting everything pressure treated seems like a bit overkill and CCA
    treated wood is nasty stuff to work with.

    cheers,
    Pete

    <> wrote:

    >Hello all.
    >
    >This years project looks set to be a large shed at mums place.
    >
    >I'll be building from scratch, as I want a challenge and to achieve
    >something better, more substantial and different from the usual stuff.
    >
    >It'll be about 18' x 8', part potting shed, part summer house, with
    >covered veranda deck area. There's a CAD render of the design at
    ><http://www.sbriggs.plus.com/shed14.jpg>
    >
    >I have a few questions for the collective wisdom of the group on
    >construction methods and materials.
    >
    >
    >The latest thinking on the base is to mount it on single brick pads (on
    >a large, existing concrete platform), then a 50x100 joist frame, T&G
    >floor, then the shed structure.
    >
    >Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,
    >50x75 sill & head. Inside skinned with 6mm WBP ply, outside with VT&G
    >weatherboard. I'll put about 30mm of Celotex / Kingspan on the inside
    >face of the wall cavity. I'm debating the need to vent the remaining
    >cavity to the outside, I can easily have a 10mm hidden gap around the
    >framing at ground & eaves level, and over the roof ridge board. Is this
    >a good idea? Should I put a vapour barrier in there somewhere? If so,
    >what to use?
    >
    >Timber treatment is another issue. While the floor joists will be
    >tanalised timber, I don't think my local timber yard has on-site
    >treatment plant, so everything else (weatherboarding, frame, floor etc)
    >will be untreated red or white wood. I could then paint or spray a
    >suitable preservative on, but would it really be worth shopping round
    >and getting the whole lot prevac treated (which adds about 20% to the
    >cost)?
    >
    >Any other construction or material suggestions welcome.
    >
    >Finally, this is grand excuse for compressor and nail gun purchase.
    >Probably the Axminster £100 compressor (2.5HP /25L /7cfm FAD) and 50mm
    >brad nailer. Are 18ga brads going to adequate for the cladding?
    >
    >
    >Cheers all,
     
    Pete C, Apr 10, 2004
    #17
  18. Steven Briggs

    Andy Hall Guest

    On Sat, 10 Apr 2004 21:31:24 +0100, Pete C <>
    wrote:

    >Hi,
    >
    >Nice plans! Might be worth considering 4" rockwool beween 4" joists,
    >would be cheaper, better and easier to install than 30mm Celotex I'd
    >expect, though a vapour membrane could be necessary.


    It isn't - I've tried it. The problem is that the rockwool tends to
    hold on to any water that gets in for whatever reason (e.g. driving
    rain against the side for a long time, among others). It is
    difficult to support it away from the outer cladding to permit
    ventilation. A vapour barrier is definitely needed and will need
    to be fitted additionally.

    For insulating below a floor it is a PITA because there is no good way
    to support it effectively.

    I made shed in this way some years ago and ended up ripping out all
    the rockwool and replacing it with Celotex.

    I've now done three buildings with it, including the garage workshop
    and it is extremely easy to use because it stays in place and is
    light. A given thickness of polyisocyanurate foam has
    approximately 4x the insulating property of glass fibre, and the foil
    on both sides provides the vapour barrier.
    It is also a lot more pleasant to work with because there are no
    fibres to stick in the skin.

    THe only slight disadvantage is the slightly higher cost, but in the
    context of a project like this and the time taken, it's a no-brainer.


    >
    >If you set the bricks supporting the floor timbers in cement this will
    >allow you to even out some variation in the concrete base.
    >
    >As far as timber goes, it tends to rot at the ends where exposed to
    >water so dipping these pieces in wood preserver then coating the ends
    >would be a great help.
    >
    >Getting everything pressure treated seems like a bit overkill and CCA
    >treated wood is nasty stuff to work with.


    It should certainly be treated with some form of spirit based
    preservative if it is to last a reasonable time.





    >
    >cheers,
    >Pete
    >
    ><> wrote:
    >
    >>Hello all.
    >>
    >>This years project looks set to be a large shed at mums place.
    >>
    >>I'll be building from scratch, as I want a challenge and to achieve
    >>something better, more substantial and different from the usual stuff.
    >>
    >>It'll be about 18' x 8', part potting shed, part summer house, with
    >>covered veranda deck area. There's a CAD render of the design at
    >><http://www.sbriggs.plus.com/shed14.jpg>
    >>
    >>I have a few questions for the collective wisdom of the group on
    >>construction methods and materials.
    >>
    >>
    >>The latest thinking on the base is to mount it on single brick pads (on
    >>a large, existing concrete platform), then a 50x100 joist frame, T&G
    >>floor, then the shed structure.
    >>
    >>Wall & roof framing I'm thinking 25x75 sawn timber studs & rafters,
    >>50x75 sill & head. Inside skinned with 6mm WBP ply, outside with VT&G
    >>weatherboard. I'll put about 30mm of Celotex / Kingspan on the inside
    >>face of the wall cavity. I'm debating the need to vent the remaining
    >>cavity to the outside, I can easily have a 10mm hidden gap around the
    >>framing at ground & eaves level, and over the roof ridge board. Is this
    >>a good idea? Should I put a vapour barrier in there somewhere? If so,
    >>what to use?
    >>
    >>Timber treatment is another issue. While the floor joists will be
    >>tanalised timber, I don't think my local timber yard has on-site
    >>treatment plant, so everything else (weatherboarding, frame, floor etc)
    >>will be untreated red or white wood. I could then paint or spray a
    >>suitable preservative on, but would it really be worth shopping round
    >>and getting the whole lot prevac treated (which adds about 20% to the
    >>cost)?
    >>
    >>Any other construction or material suggestions welcome.
    >>
    >>Finally, this is grand excuse for compressor and nail gun purchase.
    >>Probably the Axminster £100 compressor (2.5HP /25L /7cfm FAD) and 50mm
    >>brad nailer. Are 18ga brads going to adequate for the cladding?
    >>
    >>
    >>Cheers all,


    ..andy

    To email, substitute .nospam with .gl
     
    Andy Hall, Apr 10, 2004
    #18
  19. Steven Briggs

    Pete C Guest

    On Sat, 10 Apr 2004 21:56:26 +0100, Andy Hall <>
    wrote:

    >On Sat, 10 Apr 2004 21:31:24 +0100, Pete C <>
    >wrote:
    >
    >>Hi,
    >>
    >>Nice plans! Might be worth considering 4" rockwool beween 4" joists,
    >>would be cheaper, better and easier to install than 30mm Celotex I'd
    >>expect, though a vapour membrane could be necessary.

    >
    >It isn't - I've tried it. The problem is that the rockwool tends to
    >hold on to any water that gets in for whatever reason (e.g. driving
    >rain against the side for a long time, among others). It is
    >difficult to support it away from the outer cladding to permit
    >ventilation. A vapour barrier is definitely needed and will need
    >to be fitted additionally.


    It's doable. One way would be to staple support netting on the outside
    of the studs, then tack a batten on the studs to give the required
    spacing. You could also add tyvek/housewrap as well as the netting for
    extra protection if required.

    Another way would be to cut the netting to the fit the gap between the
    studs and staple it away away from the outside to give a gap.

    If the shed is in a well sheltered position you might just be able to
    put housewrap on the outside and leave out the gap.

    You wouldn't have to use a vapour barrier but if you wanted one then
    some poly stapled to the inside of the studs would do. It would give
    you a better vapour barrier than celotex fitted between the studs.

    >For insulating below a floor it is a PITA because there is no good way
    >to support it effectively.


    Again, you can get support netting for this. The netting could be
    stapled to the bottom of the joists as they are laid down, or stapled
    to the side of the joists.

    >I made shed in this way some years ago and ended up ripping out all
    >the rockwool and replacing it with Celotex.


    I take it the rockwool was directly against the cladding, and leaking
    or blown in water was soaking into it.

    >I've now done three buildings with it, including the garage workshop
    >and it is extremely easy to use because it stays in place and is
    >light. A given thickness of polyisocyanurate foam has
    >approximately 4x the insulating property of glass fibre, and the foil
    >on both sides provides the vapour barrier.


    AFIAK celotex is 60% better for a given thickness, so 100mm rockwool
    is about twice as good as 30mm celotex.

    >It is also a lot more pleasant to work with because there are no
    >fibres to stick in the skin.


    True, although if you space the studs correctly you only need to cut
    the rockwool to length.

    >THe only slight disadvantage is the slightly higher cost, but in the
    >context of a project like this and the time taken, it's a no-brainer.


    True, celotex would only work out £3/m2 dearer.

    I think it also depends on how you rate the different types of
    insulation, and what sort of deal you can get on what's available.

    >>Getting everything pressure treated seems like a bit overkill and CCA
    >>treated wood is nasty stuff to work with.

    >
    >It should certainly be treated with some form of spirit based
    >preservative if it is to last a reasonable time.


    True, any wood that might get repeatedly wet should be treated. Having
    a look at some old sheds that are starting to rot gives you some idea
    of what areas need particular attention.

    BTW my neighbour has a _really_ nice shed, I'll try and see if he'll
    let me put a picture of it up at sometime to give the OP some ideas.

    As shed styles go a lot depends on the surrounding environment, a
    Wickes type shed would't look too good next to a 17th century thatched
    cottage.

    cheers,
    Pete.
     
    Pete C, Apr 12, 2004
    #19
  20. Steven Briggs

    M. Damerell Guest

    I would like to suggest a DPC between bricks & wood. My apologies
    if you already thought of this.
     
    M. Damerell, Apr 15, 2004
    #20
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