We've got a room over the garage which has a dormer window jutting out the roof space. I noticed a few weeks back when we last had proper rain the brickwork over the garage was wet in two places, the water was running from the back of the soffits where it meets the brickwork. Sorted a little guttering joint issue out and thought I'd fixed the problem. Came home from work today after rain and I can see the brickwork is (slightly) wet.
In the photos below, you can see the pale brick has become darker from water above the garage door except in the middle, and also the leading all around the dormer and where the water is coming from. It has dried out a lot with all this warm weather, but I am concerned and want to fix it myself or get it fixed as I'm not great with heights.
formatting link
sure really where to start with investigating this. Anyone?
I cant see any pipes from the dormer gutters..where do they drain?
But it probably is just splashing from an overloaded gutter.
wont do much harm really.
Oh..from the BACK of the soffits. Mmm. I have a horrible feeling I know exactly what is happening here.
You are not going to like this.
If you get a stream of water running down the dormer sides where they meet the roof, and you obviously do, cos its wet there, then that stream will run under the flashing and drip down onto the felting. Then run down that and drip into the soffit space. That felting SHOULD overhang the guttering, and probably does..soi my guess is that its actually getting past the edge of the dfelting and running down inside the roof.
One quick thing to do is to piyut a downpipe off te dormer guttering, that diverts that flow into teh main guttering dircet.
BUT I suspect that whoever bodged that dormer in, needs his wrists slapping.
You need a good roof man up there to lift all the flashing, strip back the slates around the edge and put in lead soakars underneath the tiles. I had a similar leak in a similar place here. Those soakers are overlapping L shaped channels that run UNDER the slates and INSIDE the main flashing and form a better seal between the dormer edge and teh slates.
The idea is that any water that runs down there will not get past the soakers, and as they overlap the slates, they will channel it back out to on top of the slate below.
Oh sod it..a picture..is worth etc.
formatting link
how it SHOULD be done, and then see if it HAS been done like that. And arrange a downpipe to throw water from the dormer guttering clear of the vulnerable dormer edge.
There are three possible reasons why there is a leak. #1 at the top of the valley section under the ridge and tiles there should be a piece of lead called a saddle. This stops any water entering the joint where the ridge meets the valley. If one as not has been fitted when the mortar cracks water will get in and run inside. # 2 Check to see if there is a crack in the lead lining in the valley lead and if there is any loose bedding mortar under the tiles, this can cause suction. #3 the amount of water leaving the guttering and running down the side of the dormer cover flashing is getting under the lead. To correct this you will have to get some code 4 sheet lead at least 15" or 375mm wide bend at 90degs with an up stand of 3" or 75mm cut into lengths to the size of your tiles plus 22" or 50mm. left the present cover flashing and push up the tile that covers the bottom tile, put one of the pieces of lead ON TOP of the tile with the 3" up stand against the side of the dormer. Bend the top of the piece of lead 1" 25mm over the top of the tile; this will stop the piece of lead from slipping down. Bend the bottom 1" 25mm over the bottom of the tile. Pull down the tile you pushed up and repeat to the next tile above. The tiles should be tight against the dormer side with a minimum of 6" 100mm side cover lap. If there is a gap between the tiles and the dormer don=92t worry, make sure there is a minimum 6" 150mm lead covering the tiles NOT JUST 6" 150mm from the dormer side, Also check that the underlay felt as not rotted do to the water increase. On single lap tiles soaker are NOT PUT UNDER THE TILES but on top. As there is nothing to support them..
It is difficult to see from your pics, but there may be a sag in the guttering there, making it the point of overflow in heavy rain. Check the slope by pouring some water out of the dormer window, and check that the downpipe is not blocked at the top - ours have mesh over but this traps leaves and moss.
Secondly, if the dormer was fitted as an addition after the main house, you may find - as we did where a chimney had been removed and tiled over - that the tiling then does not quite reach the gutter and some water curls back and down the inside of the soffit. We had this both on the covered chimney and on an extension that had been widened twice without redoing the tiles properly each time.
In the latter case (discovered with this winter's snow) at one point the felt had been added at the bottom in a narrow strip which sagged between the rafters and channelled water from the soffit back into the room below - still haven't got round to fixing the plaster!
I was able to cure the wet chimney, by cutting out spare lead flashing from the earlier extension roof lines, and pushing it under the tiles with the other edge in the gutter. We are saving for a complete retile but on a complex century old building this is going to be pricey.
how long you lived there? did you do/pay for dormer in your ownership? or pre-existing?
if you lived there a while and this damp is *new* then suspect "ponding" on roofing felt, leading to it rotting and leaks through felt into top wall and down. SOURCE of leaks is what you need to sort (unless selling soon;>)) AND at least inspect/redo redo felt at eaves.....
from pics seems damp on wall is directly under eaves of dormer? both sides?
There are two types of roof tile, single lap and double lap. Right the tile lath are on, pick up the first single lap tile lay it on the right hand side starting point ok. Now look underneath the tile, and all you will see is a gap from fascia to the first lath. No support for a soaker. Right, double lap tiles, pick up the eaves tile and lay on the roof then put soaker on top of eave tile, place first full tile on top of eave tile, place second soaker on top of tile then lay tile&half on top of first full tile then lay soaker on top, carry on till abutment is complete. There are three plain tile sizes Eaves & Tops, Tiles and Tile& half.
I have been known to extend the power shower out of the window...
Sadly our downpipes go straight underground in most places, though I have chopped into one for the water butt. Still included a strainer in the hopper though, and it fills up pretty quick.
We've lived in this ten year old house for four years nearly, the dormer window was built as part of the original house design.
I thought the problem was originally due to a loose bracket screw in the guttering, causing the gutter to drop slightly at a joint. Unfortunately, correcting this didn't fix it. Looking up close at the brick where it gets wet, there is a slight lime scale buildup which would suggest it's been getting wet for some time on and off, but I hadn't really noticed it until recently.
There isn't any felting overlapping the guttering. There is none there for me to correct myself, so they must've cut it short originally.
What I do know is that last year, we claimed on the NHBC and had builders come around and remove all the ridge tiling from the main hipped roof part of our house and replace the mortar as it was literally turning to dust. So the gang that were doing the roofing during the build were a right sort. I also know that before we bought the house, a previous owner had all the fascias and soffits replaced with uPVC, so who knows what they did as part of that job.
I fix most stuff myself, but roofing is something I will have to get a pro in for. The only trouble is finding a reputable tradesman is difficult at best.
Sounds like they might have cut corners - AIUI, it is usual that replacing the bottom section of the felt, if it is short or damaged, is a integral part of replacing the fascias.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.