Drainage for drive.

[Conwy]

I am looking for advice from this forum please. We have just moved into a new house, which has integral garage that faces North. Over the last few days I have noticed that any rain blowing onto the garage door falls onto a short length of concrete under the door and flows into the garage. The Site Foreman has looked at this and tried to fob me off with a couple of excuses; they will fit a metal/rubber strip behind the door to stop water flowing inside garage, and that NHBC rules do not consider the garage to be an inhabitable part of the house. Further more, any rain is allowed to fall through garage wall will drain into the cavity wall. This last point scares me!

There is a drainage gulley at the end of the drive next to pavement, but nothing next to garage door. The driveway is flat with no slope, so any surface water will find its own level (through the garage door?). We only have the coarse tarmac at the moment, and any rain drains into this. I am proposing that a gulley be installed infront of garage, and that the front concrete section of garage floor is lowered to make water flow into the new gulley.

Are there any Building Regs that can support my request, or better, refute the Foreman's view that water is allowed to drain into cavity walls.
Thank you for taking time to read this.

[CoolBeanz]

Here's the building regs: Planning Portal - Approved Documents

Have a look for drainage, as I don't know the answer.

The first two points, I have to agree with the forman. A garage is not a habitable room, and water can get in. My garage is single brick, and it does state water can soak through the brick in really bad weather.

I'm not sure about the cavity, and drainage. I know they has to be air vents to the cavity.

I hope this helps.

[nem39esis]

Hi Conwy,

The first point to notice is that the builder is offering to do something, this would not happen if there was nothing wrong with what they have done (why spend money on something if theres no problem) that to me points to an admission of guilt. There is no way that rain on the drive should flow into the garage. If the drive is flat, the garage should have a slight slope to prevent water from entering it. Use a good spitit level to see how the garage and drive falls. If it does indeed fall into your garage and garage is not sloping in the right direction then a drain (Aco Drain) should be installed at the front to take away any drainage. The fact that a garage is recarded as a non habitable room is of no consequence as it still forms part of the property, any flooding that enters a garage should be able to drain away, it should never ever be considered ok for it to enter a cavity wall, weep holes in the wall are there so that water drains out not in, this would cause damp to form

[NewHomeExpert]

"Further more, any rain is allowed to fall through garage wall will drain into the cavity wall. This last point scares me!"
It should scare you! It demonstrates that this person has no idea about how buildings work and how to keep water out!

The rubber buffer strip does work and will solve the problem. However, it is much better if the garage floor is kept back behind the back of the door and the floor is around 15mm higher than the driveway. Not only does this stop your water problem but it means you dont see a strip of uglu concrete at the bottom of the door.

The garage is not a habitable room as far as damp and water is concerned. You could park a wet car in there. No Building regulations apply.

Your problem will get worse once the wearing course tarmac is laid to your driveway. Get the builder to cut back some of the floor to the back of the garage door as I describe, keeping the drive level below this.