leak where extension meets house

jwpetal · 31 Dec 2013

We have a new extension which is 4.2m x 5m and a pitch of 14 degrees. We are using low pitch tiles that can go down to 12degrees. The problem is that we have a leak at 3 points - on both corners and in the middle just to the right of our upstairs window where the extension meets the house.

The flashing does not appear to be in one piece. On the left hand side, there is a short piece over lapping another piece and is not flat. In the middle it appears another 2 pieces are meeting. On both sides, it looks like the flashing ends right at the end of the house i.e. it does not go over the side.

Our builder said that the rain was going the wrong way and then that he had to push down on the lead flashing. He did the latter and the leaks are worse than ever and the rain is not going in the same direction.....

I spoke to my friend, who recommended the builder, and interestingly they have had the same problem and had to get a specialist who said the work was not good. We are still in a build and owe him money for this part of the job, which we have held back till this problem is fixed. I suspect we will get the run around so I am trying to figure this out. We have attempted to reach builder etc and all are away...

I have attached pictures, but suspect you may not see much as I had to hang out a window with a small opening. Any advice would be great. We have had a couple of problems with the builder and this roof.

Alastairreid · 31 Dec 2013

Did the builder roof it then?

Even if the tiles do go down to that pitch the velux doesnt.

The lead apron can and does go in in sections as long as it has adequate cover.

The guaging is typical from a non roofer.

foxhole · 31 Dec 2013

Is the flashing cut into the brickwork, looks like it may just be siliconed to wall.

jwpetal · 31 Dec 2013

yes, it is just siliconed to the wall. should it be into the brickwork? that makes sense to me, if it should be.

If it is okay to be in sections are the sections then fused together or are they only pressed together?

The builder did do the roof and we had a leak earlier, but that was a cracked tile.

.

Alastairreid · 31 Dec 2013

The lead sheet/aprons should be overlapped approx 150mm, no need to weld or stick the joins.

It should also be channeled into the wall 25mm.

s60tsy · 1 Jan 2014

not seen the pics but the lead should be chased into the wall. overlaps are ok they dont have to be welded joins as long as the overlap is adequate

Alastairreid · 1 Jan 2014

s60tsy said:
not seen the pics but the lead should be chased into the wall. overlaps are ok they dont have to be welded joins as long as the overlap is adequate

pics are in his profile.

s60tsy · 1 Jan 2014

had a quick cock eyed new years day look, but the side doesnt look leaded against the wall and if the back isnt ground out and set in then its neither use nor ornament

jwpetal · 1 Jan 2014

Thank you for the feedback. the side is not covered and I had wondered about that. Weather permitting, I'll have to try to get to the party wall side to see if it has the same issue. I've gone out this morning and checked that the overlaps are not 150mm as well as not flattened against the bottom layer so that could allow rain in.

I am not sure about the flashing being placed into the brickwork. If it is, it is not very deep, but I can see the silicone. Do you know the depth it should be placed into the wall?

Since the flashing does not go over the edge and not overlapping properly, is the solution that it should be redone? With the amount of leakage, this would allow me to make sure the proper depth into the brickwork is met and that it is done properly or is that too much?

catlad · 1 Jan 2014

If you wanted to go out that far from your house with the new extension then you should have gone for a flat roof, you will continue to have problems until you change the design.

notagain80 · 1 Jan 2014

My wife thought I had written this as we are having almost the same problem.
Buildeer hsa said the cavity wall tray has failed sand that it has been happening a lot due to the winds and rain we have had! Wind and rain are nothing new!!

We have a small roof space and its dripping wet, coing from both sides of the bricks!

Do you have cavity walls? Has a cavity wall tray been fitted?

I have no idea what is going on with ours, other than its not fun after spending a lot of money on a build only to have it leaking!

shane12345 · 2 Jan 2014

As far as i know those tiles only go down to 15 degrees.
Leadwork needs chasing in to the wall and those velux are always going to leak at 12 degrees.

jwpetal · 2 Jan 2014

We do have cavity walls and I'll question him on the cavity wall trays and I'll follow up on the tiles. I repeatedly questioned him on the type of tiles and he said they went to 12 degrees. Thankfully we have not had any other leaks....so far.

It is so frustrating as we had a flat roof, very cold, constantly leaking extension before and decided, instead of a loft conversion, we'd rebuild the extension. At least it is warmer, just not dry.

jwpetal · 2 Jan 2014

Just got a visit from building control and he advised that the work had not been done correctly and the work must be corrected. Corners were not done as mentioned on this site and that there should be 2 parts to the work and one part was done incorrectly. So now to find a roofer and or get the builder to correct the problem.

He also mentioned that the work around the Velux windows was not done correctly. He said the pitch of the roof should not be a problem if the other work was done correctly. He was relieved to learn that we had not paid all our money to the builder and said that the builder should call him if there are any questions.

Thank you for all your help.

jonez · 2 Jan 2014

Unless the Velux windows are intended for a flat roof 14 degrees is too low. This is what Velux say on their site..

Is installation of VELUX roof windows possible at any roof pitch?
Yes. Centre-Pivot Roof Windows are designed to be installed on a roof pitch from 15°-90°, depending on the roofing material and flashing selected. Top-Hung Roof Windows are designed to be installed on a roof pitch from 15°-75° (55°-75° with the use of special springs), again depending on the roofing material and flashing selected. VELUX also offer a range of flat roof solutions which can be installed on roofs with a pitch from 0°-15°

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leak where extension meets house

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