Hi,
It's a few years since I installed new flood defenses to our bungalow Oscar but ours was a patio not a decking although I'm happy to post what I did. I had re-laid the patio years ago because with a downpour of rain water could reach 6" deep by the back door meaning lots of sweeping to prevent it getting into the bungalow; we live on a steep valley side with a large rear garden giving a great deal of water run off. I cured the pond by arranging a fall to the side garden hence no more ponds. Over the years though water was gaining access in increasing volume under the bungalow floor where I ended up removing four bucketful's at a time and it was getting worse so I finally got around to sorting it out but I never ever take the simplest or easy route I prefer to graft and struggle doing the best job I possibly can.
I lifted the row of 3' x 2' x 2" paving flags adjacent to the wall allowing exposure of the foundation. It soon became clear where water was entering; it was through the wall to foundation mortar joint which had failed. I could very easily raked out the joint and apply new mortar but having got this far I never wanted to do the job again so I dreamt up new flood defenses.
Here's the failed mortar joint raked out.
I never take the easy way out and I gave the job a great deal of thought; we were fed up of open drains gathering leaves; slugs and lots of slimy debris so time to sort these out too. Above shows a selection of old drainage.
I prefer to buy rather than hire so I bought a new electric cement mixer through eBay; no sooner did this arrive than the new trench filled with water and it rained for a week or more stopping work whilst we walked the plank to gain entry into the bungalow.
I knocked up a strong mortar mix and made good the faulty mortar joint but then added a course of fully bedded engineering bricks completely sealing the wall to foundation mortar joint; lets see water get through this? Still not enough I then created a concrete based brick walled channel again using engineering bricks the concrete base 4" thick mixed in the new mixer. Here the concrete has set allowing work to proceed.
The new water channel under way; it slopes from the back door to the top of the picture where the channel ends but then at right angles I installed a 4" diameter soil pipe allowing any water to discharge harmlessly under the hollow pathway to the bungalow side.
Here's the new channel and also new plastic drains with washing machine and kitchen sink outlets; rubber coupling was used to connect the new to the old.
Almost completed ready for flag laying; all drains were fully tested; any water running under the flags will now be collected and discharged via the new channel. It was a shame to cover it all up after such a lot of hard graft working entirely on my own with my lovely wife supplying encouragement and many mugs of tea.
This is how I replaced the open drains and I've never seen it done previously; I brought the new plastic drain up to flag top level and opened up an end cap to accept closely fitting kitchen outlets; these tend to foam a bit whilst the washer discharges but it's not a problem and looks a great deal more neater than stinking open drains full of slugs.
Who would guess so much thought and effort had gone into what is now out of sight.
Here's the picture to the rear door showing the gutter fall pipe also neatly run into it's new plastic drainpipe. All flag joints are fully filled with mortar even right up to the bungalow wall; air bricks and DPC are uncompromised; I'm not a builder but a mechanical engineer; if I can improve on anything original I will do so; I could have saved a great deal of work just sealing the faulty mortar joint but I'm not scared of hard work so as I said earlier I did the job to the best of my ability thinking it all through before even making a start on repairs. No more water ingress worries and no more smelly open drains to clean out often; just inside the bungalow I fitted an automatic air vent when I replaced the roof to get rid of the original 4" pipe that vented through the roof; this looks excellent compared to what it did.
I looked after the new cement mixer and owned it for about six weeks it still looking like new; I sold it through eBay only losing £20 so pretty good value for 6 weeks ownership compared to hiring.
Good luck with yours and think the job through before starting to see if you can make improvements.
Kind regards, Colin.
