DIY Doctor UK DIY Forums

hi all

im new here and inexperienced in building matters. recently started a project on back garden. Tore down the old brick toilet and lifted the old patio.
Previous owner had laid patio up to level of French doors but there has always been a 2 brick drop to get inside the house.
Ideally the French doors should be 2 bricks lower to match dpc. So I had a friend lay my new patio but the problem was the whole back garden slopes towards the back of house.
He suggested digging out and laying patio sloping towards house but have aco drain butted to house to carry off standing water but this was always going to be above dpc by about 3 bricks.
Also have blocked off 2 airbricks in process.
Internally I have 2 level floors but ones solid and ones wodden due to 2 rooms being knocked together.
So here lies my concern - will the aco drain cause a bridge for damp to get across.?
I was thinking of using a dpc paint 3 bricks up from aco to stop penetration via splashback from rain. help anyone

thanks

the blocking of the air vents is a concern, you will need to install periscope air vents to allow the air to circulate, as for the splashback use a clear silicone solution and spray the wall to protect it.

thanks for advice welsh brickie

unfortunately the patio is down now. so installing a periscope would mean ripping up some of the patio and aco. will it be really detrimental leaving it covered. it has already been covered for years with previous raised patio. cannot lift boards inside as we have permenant karndean flooring down.

how about making a gap in flooring under kitchen units to allow some kind of flow?

thanks again

you can cut the brickwork out from the outside above the aco drain and install it, its awkward though but possible

thanks welsh brickie

the wall doesn't have a cavity, does this make things a lot more of a difficult job?

ps if you north wales you can quote the job. im on the Wirral

you would have to cut a hole through the whole wall then, and then knock the bricks out through to the floor, and form a duct with tiles or slate, like I said possible but a pig of a job.
Sorry mate I am residing in turkey at the moment doing up a house, so cant do it

welsh brickie

I have thought about my dilemma and have decided on a new route to cure my bodged patio. can you advise me as I go?

I have decided to cut out the aco against the wall and dig down to expose dpc and airbricks. I will also take out 1st run of paving to achieve this. my aim is to put a linear drain below dpc and airbricks and build back up the patio but leaving a gap of 150mm from patio to back wall with a channel cut out against back wall where aco vused to be.there will be a drop which I need to bridge for safety for my little boy. I vwas thinking of using galvanised grates from previous aco to cover the drop. I was going to fix angle iron to back wall level with patio so aco grates sit on angle iron and a "lip" just under patio achieved by breeze block retaining support.

questions.

how to protect the wall from splashbach from grates?

will angle iron hold water causing it to creep into interior plaster causing damp?

thanks for your help

d13

you could do that or get a steel grate fabricated to fit with feet so it rests on the aco drain, As for water splashing against the wall, you can paint a clear silicone solution like aquaseal

thanks welsh brickie

would aquaseal need to be applied all over wall down to aco or just in splashback area? I would imagine a grate wouldn't create as much splashback as a solid patio against a wall would.

good idea for legs on grate

cheers

d13

just the splashback area will be enough

welsh brickie

do you have an external link for the aquaseal? looked but cannot find product. builders merchants not heard of this brand

thanks

its a silicone paint, dries clear, aquaseal is a brand name unusual a builders merchant has not heard of it

OP,

in your first post you mention "digging out" the patio but next post you seem to say there's nothing to be done with the patio? Which is it?

What you propose ref drains and grates will probably take as much time and effort as dropping the ground level & relaying your patio to slope away from the house. In virtually all circumstances, you do not lead water to a structure, you deflect it away - esp. on a hillside.

If the only sub-floor ventilation in place is now blocked, then new ventilation must be provided.
Suspended floors require cross ventilation.

Are you saying that there is no floor access trap anywhere? If so, then it might pay you to cut a trap in an inconspicuous place - believe me, apart from the above issue, you will need sub-floor access sometime, probably in a hurry.

Where is the splashwater coming from - the guttering? Deal with causes not effects.

Are there any signs or smells of damp in the room?

Maybe some pics would help us.