Hi... conservatory project

[3narf]

Hello!

I'm going to be starting a project shortly to build a conservatory on the back of my house.

It will be 3m x 5m to avoid planning issues. The ground is flat, access to the garden via a gate from the driveway.

I'm quite good with most practical things but I've never had much success with concrete and I'm seeking a bit of basic advice with the way forward. I'm planning on doing virtually everything myself to save money (I've had some outrageous quotes for the base - I know I live in Tetbury but I'm a northerner) although I might hire some labour on a day rate basis for brickwork etc. It will probably be a 2nd hand hardwood conservatory, with or without a dwarf wall - whatever is available at the time.

OK! First of all, I lack even the basic knowledge of how to build the base. I assume I dig out the footprint to 600mm and fill the hole with concrete... What size of skip will I need for soil? 5 x 3 x.6 = 9m3, and double it for good measure?

Thanks in anticipation... Andy

 

[3narf]

On here

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[Doghouse Riley]

I'd contact one of the concrete suppliers, either ready-mix or barrow mix.

Givr them the dimensions of the base you need. They'll calculate what you need and how to do it. From this yo'll be able to work out the volume of soil you need to remove and what size of skip you need.
The ideal ones are those with a drop-down door so you can run a barrow up a scaffolding plank.

I dug out a 9' X 12' X 5ft 3000 gallon koi pool that way.

 

[3narf]

If I build a rectangular base, and the conservatory I find is half octagon shaped, will it look rubbish?

 

[Doghouse Riley]

If I build a rectangular base, and the conservatory I find is half octagon shaped, will it look rubbish?

Build a half- octagon base, with say, a 2ft wide path around the front of the conservatory. You could cover it with some of the flags you'll be removing. You could hire an angle grinder to cut them. "Everything is poossible."

 

[3narf]

Build a half- octagon base, with say, a 2ft wide path around the front of the conservatory. You could cover it with some of the flags you'll be removing. You could hire an angle grinder to cut them. "Everything is poossible."

Thanks! So it's ok to just put in concrete, then put a dpc, insulation, dwarf wall etc on top of that? I suppose that's what we'd do if there was already a concrete patio there...

 

[Doghouse Riley]

Thanks! So it's ok to just put in concrete, then put a dpc, insulation, dwarf wall etc on top of that? I suppose that's what we'd do if there was already a concrete patio there...

Soumds like a plan. You're not talking a lot of weight on top of your slab, But take the advice of the concrete supplier regarding preparation and thickness of slab.
I used bits of old pallets as shuttering when I built my koi pool collar and path. Cheaper than buying wood.

 

[3narf]

Ok! I'll build a base to the maximum dimensions, allowing 300mm or so extra.

Do I need to leave a slight gap between the base and the wall of the house?

A conservatory has come up on ebay but it's 3.25 metres... how strict are planning departments about dimensions? I suppose if anyone suspected it was oversized (the surveyor who lives next door, for instance) and reported it, I'd have to take it down...

 

[Doghouse Riley]

As long as you aren't covering up any air bricks, it should be OK.

In my opinion, it's best to treat the planning department as a "friend."
Ring them up about your concerns regarding size. Preface your conversation with, "I need some professional advice," they'll fall over backwards to help you.

 

[3narf]

I appreciate your advice with all this! As you can see I'm pretty clueless...

 

[3narf]

Does the shuttering have to go all the way down to the soil or is it only important for the top bit? Do I have to divide the slab into 'cells' or is it ok in one piece?

When I put the screed on top, do I need to put in more shuttering? Or just extend it up a bit?

Thx again

 

[Doghouse Riley]

Does the shuttering have to go all the way down to the soil or is it only important for the top bit? Do I have to divide the slab into 'cells' or is it ok in one piece?

When I put the screed on top, do I need to put in more shuttering? Or just extend it up a bit?

Thx again

I'd make sure that the shuttering gives the slab a firm edge to the sides down to the hardcore, you don't need bits breaking off ikf it is the edge of the p[asth around your conservatory, you also need a nice straight edge at the top so you casn make sure the screed is level, you do need a decent spirit level and a long piece of straight wood to set it on.
My patio raft which is bigger than your conservatory base, was poured in one go, no cells.

 

[3narf]

Hardcore? Do I need a layer of this before the concrete? Would that be part of the 600mm depth or in addition? Thx again!

 

[Djwilliams37]

Hi
Have you considered a steel base? I put my own conservatory up using one as I didn't want the hassle of a concrete base and Dwarf wall construction. This has been up since 2007 and never had any problems with it. The Dwarf wall comes as sectional box sections with brick slips to make it look like a real wall

 

[Doghouse Riley]

Hardcore? Do I need a layer of this before the concrete? Would that be part of the 600mm depth or in addition? Thx again!

Some hardcore would cut down the amount of concrete you need.

 

[3narf]

Hi
Have you considered a steel base? I put my own conservatory up using one as I didn't want the hassle of a concrete base and Dwarf wall construction. This has been up since 2007 and never had any problems with it. The Dwarf wall comes as sectional box sections with brick slips to make it look like a real wall

I will look into those, thanks... I'm hoping to find a conservatory that doesn't need a dwarf wall.

 

[3narf]

Some hardcore would cut down the amount of concrete you need.

And it's cheaper, presumably! How much would I need? Half the depth, or less?

 

[Doghouse Riley]

And it's cheaper, presumably! How much would I need? Half the depth, or less?

A lot depends on whether or not you have a dwarf wall and how high it is, as bricks are heavy.
As I mentioned before, have a word with a concrete supplier.

 

[3narf]

Hi, me again. I've finally got my project started. Base is currently going down, at garden level; in the new year we'll be building it up to the level of the living room floor, with DPC & screed etc.