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Bricklaying
Air brick and french drain
I am currently buying a house and during the survey, it has been highlighted that the driveway was not done according to the regulations. Indeed the distance between the ground and the air brick is less than 75mm.
The drive way is paved and the slope is in the direction of the house. 20 cm from the walls of the house, there is a a gutter to drain the water of the driveway.
Between this gutter and the wall, there is 2 rows of bricks. The height between the driveway bricks and the air brick is approximately 1 brick.
The surveyor advised me to remove this 2 rows of bricks, dig about 150mm at the edge of the house wall and put a gravel up to 750mm from the air brick.
Should I do this all around the house? or should I dig a patch in front of the air brick, provided that the ground below is soft??
Also, the previous owners have build a terrace, which is at the same height as the air bricks. In the same way, should I cur the tile of the terrace a create a patch of gravel as per the question above?
Many thanks in advance for your answers
4 Answers from MyBuilder Bricklayers
Best Answer
You are better off doing it all the way around the house
Answered 8th Mar 2020
there is a min magical figure of 150mm below DPC (or airbrick level in your case) where all hard surface should be terminated, the theory being rain will not splay more than 150mm and breach the DPC, in some cases you can see a shingle bed against the building where the 150mm rule has been ignored, the theory being rain will not splash as high when it hits shingle but with your drive being so high I would recommend you go with the surveyor
Answered 8th Mar 2020
Hello bds 29 i agree with John Crawley as we all know it rains alot and you gonna have problems in the future if not fixed
Answered 8th Mar 2020
As the ground level should be 150mm below dpc, assuming that the airbricks are in the course directly below dpc. Yes you are better doing this all round the house. Re the driveway, if the driveway slopes toward the house, then possibly an acow or Channel drain can be installed and discharge into an existing rain water drain. I would have to see the layout, to confirm.
Answered 14th Mar 2020
