Garage build - Upto DPC now how do i do the base

26 Apr 2015
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United Kingdom
Hi, I should of probably made a WIP thread but hey, following on from other posts I've put up i'm now near enough ready to start sorting out the concrete base. Heres some pics:

I just need to do the back wall and then i'm ready to sort the base, so looking for abit of advice on the best way to do it?
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100 - 150mm trowel finished concrete on 1200g polythene on 25 - 50mm sand blinding on compacted MOT stone (the depth of which will be determined by finished concrete height).

Often the DPC layer and the finished floor heights are different in garages due to the fact that the garage floor and the external ground are usually the same height meaning the DPC will often be 150mm higher than the concrete floor of the garage. If this is the case then tying the floor membrane into the DPC can mean that the 150mm membrane upstand is likely to get damaged. It can be either tied into the DPC via the back of the blocks (cavity wall only and this would need to be done prior to building the course directly beneath the DPC) or leave it cut off just above the concrete.
Ok that makes sense. Is there any advantage of tying in the floor Dpm into the wall? Or is it just the same as putting a separate one on the wall?

Also do you think I should dig out the random bricks on the floor before i start prepping for the floor?
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I also put 100mm kingspan in mine so I can use it for other things if I ever needed too. My guys also put steel mesh in to reinforce it it was a double garage so maybe that's why they did it or possibly due to the kingspan being user it all.

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