Rain soaking through garage

MikeJXE

HatMan92 said:

EssexExile said:

I'm with "subjecttocontract" above, the ground outside is above the garage floor. That can't be right, surely the builder should sort it out. Otherwise just lower everything close to the garage to below floor level.

MikeJXE said:

Why are you asking this, if it is a new build then it's the builder to sort out. 

Ordinarily yes, we've still been working through the snagging list which had some more notable & significant issues and this has only been this bad this winter; we fell out of the warranty period towards the end of last year. So basically we've missed our shot, and would have to take it up with NHBC.

NHBC will investigate it, but as it's a garage, their own technical standards hold that it's unreasonable to expect a single skin garage to be waterproof / immune from damp as it's not designed in accordance with their technical standards. Also the NHBC policy will only pay out of the cost of works exceed the threshold value which is close to £2000, so either way I'm going to have to pay a tradesman or do the work myself.

I'm fuming, but mostly I just want a dry garage.

diystarter7 said:

Hi
Is the outside sill very slightly sloping into the garage? And or levelish but allowing water to gather and then pour through a gap?


Thanks

Having just been out there, there doesn't seem to be much of a slope on the patio at all. 

So do the NHBC technical standard say the ground around a garage can be at any height ? 

You're not going to get a dry garage if the surrounding are is too high. Even at 6 inches below dpc there is still the splash of heavy rain. 

Remove the solid ground, fill to  at least to 6 inches below dpc with gravel and that it can drain away somewhere. 

Keep paving 9 inches away 

Section62

HatMan92 said:

What I am understanding from your comment is that if I cut back the pavers and lay aggregate in the gap, and I continue to have issues on the same scale, then the installation of further proper drainage is really the only way to go in terms of long term rectification?

Yes, more or less.

You need to dig down a reasonable depth along the wall, line it with geotextile and backfill with no-fines gravel/aggregate.

If you are doing that already then it won't be much more work/cost to add a length of perforated pipe in the bottom of the trench.

The difficulty is in finding an appropriate drain for the water to discharge into, and one which is deep enough so the flow will go from the pipe in the trench into the drain and not the other way round.  It is possible the drain from the garage RWP is very shallow.

I also still wouldn't rule out the possibility the RWP drainage isn't connected correctly and the area around the door is acting as an unwanted soakaway.

Ideally, in theory, you'd get a professional drain survey done.  In practice I know of people who have managed to do a reasonable job using a cheap (£10-£15) "USB drain camera" - google those words and you'll get an idea of the kind of thing.  One which is 5m long should take you far enough to be fairly sure water is getting away from the garage, but you may need to be creative with methods of getting the camera to go that far along the pipe.