New build garage retaining wall wet

[Anthony j]

Hi all just moved into a new build and the garage retaining wall is wet is this a building fault the retaining wall is for about 1.5 metres the other side is garden grass level any information would be great thank

 

[KenGMac]

Anthony j, good evening.

Am I correct in assuming the retained external earth is 1.5.m deep.?

If a new build, then the developer should sort things out under the snagging system.

Most common cause of such defects is a defective or?? non-existent Damp Proof Membrane, in short the external surface of the area of the retaining wall below ground should have an impervious layer of "Damp Proof Membrane" to stop ground water entering the structure, this vertical membrane should also be connected to the damp proof membrane below the floor slab.

Ken.

 

[Anthony j]

Hi Ken yes from the inside of the garage that wall and the back wall of the garage are retaining so the ground level on the other side of the was are 1.5 metres above the ground level of the garage floor and its just this patch that is wet so damp proof membrane this missing or damaged thanks for your help will thay have it fix it I'm guessing thay will try and not to

 

[Ian H]

What would they use for the membrane? Something stronger than the floor stuff?

 

[KenGMac]

Ian H, good evening.

My preference would have been "Bituthene" and a Bituthene primer on the surface of the external wall.

"Bituthene" -- a very, very, sticky backed thick plastic membrane

But given the degree of moisture penetration who knows if there is indeed anything there to stop ground water?

Ken.

 

[Leofric]

The dpc is 2 courses of brick above the garage floor level so it does look like they have not considered the damp proofing aspects of the ground being 1.5m above garage floor. Bearing this in mind I would want to know if the wall is thick enough to retain 1.5m of earth. You would be looking at 330mm of bwk at least at the base of the wall.
ps haven't got my standard retaining wall details in front of me, may be even more than 330mm.

 

[KenGMac]

Must admit, I missed the DPM, still struggling to see it?

To O/Poster, a DPC --Damp Proof Course---[as opposed to a DPM Damp proof membrane] Is a horizontal water proof layer laid on to the brick coursing as the wall is built, stress the word Horizontal as opposed to vertical on the external face of the wall. Apologies if this explanation is totally unnecessary?

Ken.

 

[Leofric]

Must admit, I missed the DPM, still struggling to see it?

I was referring to the horizontal dpc in the bwk, I can't see any sign of a dpm either.
ps there should be a horizontal dpm under the floor of course., but in this situation it would be interesting to know how they have turned that up the wall It all needs further investigation.

 

[catlad]

It doesn't make sense to me has that pier been added as an after thought? its obviously wrong with all that water coming through the brickwork.

 

[KenGMac]

Must admit, I missed the DPM, still struggling to see it?

If you enlarge the image with the block work pier, there appears to be a DPC between the concrete floor slab and the brickwork? odd in a retaining wall scenario?

If the O/Poster is still reading all this Teccy building jargon the basic concept is something is not right, the Developer will have to address these issues.

Ken

 

[Anthony j]

Hi all thanks for all your help afew more pictures the block work is wet as well and has dpc buy the looks of it

 

[23vc]

Wall was originally built as if ground level was lower, then the 1.5m got back filled/built up during landscaping? Is my guess

+ that 3rd outer skin looks like a retro fit , courses don’t line up

 

[^woody^]

If you have a Buildmark Warranty from the NHBC, then claim on that.

The wall has not been designed or built in accordance with section 5.4 of the NHBC technical standards (damproofing).

 

[Leofric]

If you enlarge the image with the block work pier, there appears to be a DPC between the concrete floor slab and the brickwork?

The dpc is 2 courses of brick above the garage floor level so it does look like they have not considered the damp proofing aspects of the ground being 1.5m above garage floor.

- as I see it.

 

[Leofric]

The wall has not been designed or built in accordance with section 5.4 of the NHBC technical standards (damproofing).

- and structural design as a retaining wall for that depth of earth needs looking at as well.