Water Leaking In But Nothing Obvious

[H2oDunc]

Hi, I am after some building advice. We had a lot of heavy rain the other night. In the bedroom the top of the outside wall where the wall meets the ceiling were several wet patches. See photo's. Within a short period of time a lot of water was on the floor but with no obvious path from the damp at the top of the wall to the floor. The next day I check for missing roof tiles etc. but all appears OK on the roof side of things. Any ideas on how its getting in would be appreciated, Cheers Dunc!

[sometime]

Hi, I am after some building advice. We had a lot of heavy rain the other night. In the bedroom the top of the outside wall where the wall meets the ceiling were several wet patches. See photo's. Within a short period of time a lot of water was on the floor but with no obvious path from the damp at the top of the wall to the floor. The next day I check for missing roof tiles etc. but all appears OK on the roof side of things. Any ideas on how its getting in would be appreciated, Cheers Dunc!

A few pictures of the outside wall and roof area would be helpful.

[trogers]

Looks like you have a concrete flat roof that has no heat insulation from the sun as seen from the crack lines at the ceiling plaster. The cracks at the border between ceiling and wall, especially at the corner, is due to thermal expansion/contraction of the roof slab forcing the wall to incline outwards and inwards.

Check out the position of the parapet walls on the roof and see if they are located in line with your room walls, or if they were built further in. When the latter, the surfaces between the parapet walls and the edge of the roof slab will not be waterproofed. Also, is there any 'throat' (or groove) built into the underside edge of the roof slab? If not, rain water flowing over the edge of the roof slab will traverse along the underside and on to the lines between wall and roof slab.

[lopburi3]

Is the paint on the outside wall good? If water was driven by wind it can easily penetrate cement (mostly sand) wall if not waterproof. I had to cover an outside section with waterproof cement to stop such a problem. At another area used many coats of latex paint (allowing each to be absorbed by the cement/sand). Both have prevented any further problems.

Edited May 24, 2009 by lopburi3

[H2oDunc]

Cheers guys here are some roof pics. Not a flat roof as has been said. Thanks again Dunc

[loong]

Is the ground level outside higher or lower than inside?

If GL is higher or the same, water can seep through the wall

[loong]

Oh, and clean the roof valley, the debris in that wont help

[lopburi3]

I can not see any protection under the tile eves to prevent rain being blown under the tiles into the ceiling area during windy weather. Normally there is cement board in that area. But it may just be the photos.

[trogers]

Overhang of roof sheets to the wall is rather short. Strong wind can blow rainwater into the voids between roof sheets and fascia board, into the underside of the roof space.

[lopburi3]

Best to have underside of tile sealed as in photo - although this is a much lower slant so even more important that the seal was total.

[H2oDunc]

Cheers guys. It only seems to be a problem when the rain is either very heavy or when there are high wind as well as the rain. Wlil get somebody to come and give me a quote!

[teacup]

Based on the pics provided above

Least likely the valley is the problem here, but it is just a typical case of ......"Not enough roof overhang"

The water ran down the roof, and got blown-in by the wind at the bottom to the top of the wall .....not to mention there is no gutter system to catch the rundown water.

and

whenever it's windy, the rain would get blown-in by the wind...to the top of the wall.

Edit: guess I'm 3 mins too late huh...lol

ok nevermind

Edited May 24, 2009 by teacup

[loong]

H2O, have you checked the ground level outside? Is it well below the inside floor level?

[H2oDunc]

Loong the level outside the wall with the problem is below the floor of the bedroom. he top of the wall near the ceiling was damp but the amount of water on the floor was a lot compared to the damp patches. I will get a farang builder somebody recommended to come round and have a look. Cheers al for the quick advice Dunc

[lopburi3]

The damp patches will drip the water from the lowest point so not unusual that most goes directly to the floor rather than the wall.

[Beardog]

Have the same roof in our casa. The problem is if you go into the attic through the access panel with a flashlight you will see condensation where the metal roof ties go through the tile to your steel to hold the panels down. Our kitchen & bathroom have the identical scenario & I was amazed at how much condensation gradually goes to the ends. I think you will be able to see more & get a clearer idea on how to fix it if you can actually see a point of entry. The Thai way is(if they use the drill studs & put them through the tile) is to put some goop (best to use a oil base Silka caulking even this is not the perfect solution. The next house we start on soon will have a proper c-pac tile roof now that I know about the pitfalls of the asbestos type tiles. We replaced the front already & the back I am going to cement the tiles where we are getting wind drivin water. Idiot that built the house decided a 10 degree pitch (if that was alright but forgot to do something about the rolled edges) the water can come in & just run down the interior wall. Once the edges are sealed it should stop the rain from back flowing in. Since it was a 210,000 baht quickie with knowing I was going to build the real house I don't care if the back roof looks pretty. The other way I used to seal the other condensation leaks was to lift the affected panels & put Silka oil based caulking all the way down the edges & re insert the panels.

If the tiles are not the proper size as mentioned in this post that to will affect the way the roof works. our front of house were 120cm tiles mixed with 150cm tiles. the contractor saved a minor amount of baht but is a real pain as the job had to be done twice & extra support metal for the new longer panel to match. They should be the same size -no mix & match.

Good luck it might be a long season!

Barry

[Rimmer]

I'm surprised you can keep any water out!!

The overlap is not enough. there are two sizes of those asbestos tile things and looks like there should be one more row giving you a good overlap. I forget the recommended overlap but the builder shop will tell you.

Also the builder has used standard gutter bolts instead of the the readily available clip that is fastened to the roof rail and clips the front of the panel down. It is plain folly to punch holes in a roof all be it on the top of the ridge. Only garden sheds and the dog house out back use this method.

You need to seal up ALL the bolts AND the gaps where they overlap. Use a ladder and planks or you wil go through.

Edited May 24, 2009 by Rimmer