flat roof on garage - drainage problems

[frustin]

With all the rain this weekend there is a big puddle in the garage near to the wall and it's very damp plus it is clear water has been running down the wall.

The garage is of brickwork construction set beneath a flat steel profile sheet covered roof.

I got the ladder out to see if there was a problem with the guttering, there isnt, no blockages. I poured water into the gutter to check.

The next thing I tried was pouring water onto the roof itself. Despite the flat roof the water runs off toward the guttering. Here seems to be the trouble: the water doesnt fall into the guttering, it goes underneath the roof and then...down the wall, bypassing the gutter! Much like when you try to pour water from a cup with no lip into another cup, it sort of spills down the side of the cup.

So what I am thinking is to hammer a lips into the garage roof where it overhangs the guttering. does that seem ok?

Untitled

• frustin
• 30 Apr 2012
• 1

 

[wingcoax]

Whoever laid the roof panels did not overlap enough. You need at least an inch to ensure the water drops into the gutter. Hammering over would not be a good idea as you don't have much to play with. Can you insert a short piece of panel under the existing panels, allowing an inch and a half overlap?

 

[cotswoldbuilders]

Fit some felt/gutter refurbishment trays.
They come in 1.5 lengths, you should be able to prise the tin up enough to slide them in or remove the bottom fixings first.
They are rigid and have a curve on one end which will lap into the gutter.

 

[frustin]

thanks all. i have some felt i used for the shed.

 

[frustin]

Fit some felt/gutter refurbishment trays.
They come in 1.5 lengths, you should be able to prise the tin up enough to slide them in or remove the bottom fixings first.
They are rigid and have a curve on one end which will lap into the gutter.

I used felt left over from the shed roof letting it hang into the bottom of the gutter. Roof and gutter sealant between the tin and felt.

It took me about 1.5 hours in total as a tree needed lopping and a water butt moving, before i could get to the end of the garage.

It rained last night and the wall is still dry.