Bay window roof repair

[ChrisD]

I'd be grateful for any guidance on the following issue:

We have a 1950's bay window at the front of our house. The roof covering is in need of urgent repair. Our friendly and reliable local builder has quoted for repair for a mineral felt roof and re-rendering of the portion under the old arch (see photo). The problem is that he is recommending mineral felt (a greenish colour) and, of course, cement based render - both of these things I am extremely uneasy with. In an ideal world I would insist on a lead recovering and no cement. Unfortunately I believe that lead, in this location, would last about until the evening and that lime mortar would not be best suited to an application designed to keep moisture out. I am currently heading for a solution that is, at best, a compromise - in my builder's words - a 'necessary evil'. Can anybody advise on a better course of action?

TIA.

Chris.

 

[Feltwell]

What's the roof covered with at present Chris?

You say lead "would last until the evening" - is that because of theft I presume?

Mineral felt "flat" roofs, if done well, can last 40+ years. If done badly they can fail within 10.

You remove the render that is there at present and replace with lime render and it will perform perfectly well, but equally (says he taking cover) I can't see that a tiny area like that of cement based render will do your building any great harm.

I've got a similar dilemma with my (original) Victorian bay. It has a felt roof at the moment which is sound, but the design of the bay is such that the water drains to a channel at the back of the roof, against the wall. Nothing wrong with that, it's all watertight, but when they felted the roof they left a slight forwrd facing slope on the front section of the roof such that some water drips over the edge - which is slowly causing the window to rot at it's base and not helping with damp in the wall below the window. I have to decide if I go with another mineral felt roof or get it done in lead.

 

[Flyfisher]

Is the area particularly rife with lead thieves? I wouldn't have thought that such a small bit of leadwork would attract such attention, but perhaps that's just wishful thinking. Anyway, would the top of the window be particularly visible?

 

[Penners]

I agree with both the above responses. The photo suggests that there wouldn't really be enough lead to attract the attention of thieves. But a well-laid mineral felt can last for a very respectable time.

There are also newer flat-roofing materials. I believe butyl is often used nowadays, and is said to have a very long life. But it it's a fair bit more expensive than felt, and I believe laying the stuff is a very specialist job.

As for the rendering, like Feltwell I don't think I'd lose too much sleep over a little patch of cement like that.

 

[ChrisD]

Thanks for the comments. I was also surprised to find the cost of lead sheet to make the necessary repair would be 300 pounds. Scrap value would be a bit lower but I think that the only way to make it more tempting would be to re-cover with 20 pound notes. Being a rural community we do have a lot of trouble with........ I mustn't use the 'P' word........... oh well......

I'm very sorry about that.

I only want to do this job once. Lead would be the way to go if it wasn't in such an obvious and accessible place. The bay is currently covered with old felt, which being old and knackered, blends nicely in with the rest of the house. My objections about the mineral felt and cement are purely aesthetic - there are external repairs in cement elsewhere on the property that just make me wince when I see them. The builder says that his work will be noticeable at first but will blend in when weathered - which I hear as 'it will look bloody awful but you'll get used to it'.

What I think I am hearing here echoes my lovely wife's comments - 'stop dithering and get it sorted!'.

Correct?

 

[Penners]

What I think I am hearing here echoes my lovely wife's comments - 'stop dithering and get it sorted!'.

Correct?

Good heavens, no! If we all stopped dithering and got it sorted, where would we find the time to faff about on this forum?

My wife thinks I visit the forum regularly in order to give and receive good advice. :lol: :lol: :lol:

 

[worms]

I believe butyl is often used nowadays..., and I believe laying the stuff is a very specialist job.

But is it? Or is that simply builders hype? I guess it depends on the size of the roof, but handling a single, large, sheet of pond-liner and having no joints to seal is surely easier than working with individual lengths of felt?

 

[Penners]

Well, I can't say for certain, but so far as I can gather the seams are "welded" in some way. I really don't know whether it's builder's BS or fact, but I'm pretty certain my mate's MIG welder wouldn't be up to the job.

 

[MatthewC]

There are other alternatives: "Terne coated stainless steel" is approved by English Heritage in cases where they will approve a change in material from copper or lead, and I also found reference to stuff called "Preseal" (http://www.preseal.co.uk/lead-alternative.htm) which claims to look like lead with a life of 50 years. (NB It also claims that it is non-recyclable and so is not prone to theft, but if it looks like lead then will it get taken anyway...?)

 

[philpjuk100]

Fibreglass? my father had a small square bay done in this,it was grey in colour and looked more like lead than felt does.It was troublefree for the five years until the house was sold.There is a firm called FRS (fiberglass roofing supplies) who sell the materials.phil.

 

[chuckey]

The first job is to sort out that "white" blob to the right of the old brick arch lintel. There is clearly a lack of mortar around it and until its tightened up, the arch will move and drop with the attending requirement of re-pointing above it.
Providing the wood wooden frame is OK, I would rebuild the roof like one builds a boat. Strip of old roof. Carve up polyurathane foam blocks to provide a nice curved back edge to match the bottom edge of the brick arch. Stick'um on with a modern adhesive. Glass fibre on three layers of woven material with a 3" overlap, stapling the bottom layer on to the woodwork. Finish topcoat with a dark finish. When cured, trim of bottom edge and flash the top into the mortar joint. If done properly it will require re-painting with two pot paint every 10 years, but its waterproof and adds a bit of linsulation.
Frank

 

[Moo]

We have a 1950's bay window at the front of our house. The roof covering is in need of urgent repair.

It could, of course, be a good excuse for replacing the window with something.......

 

[Penners]

We have a 1950's bay window at the front of our house. The roof covering is in need of urgent repair.

It could, of course, be a good excuse for replacing the window with something.......

But, d'you know, judging from the photo, I think the window itself looks rather nice.

 

[Moo]

judging from the photo, I think the window itself looks rather nice.

I've just had a little hunt through earlier posts and can't find the picture of the whole frontage that would enable me to decide whether I agree with Penners.
Is there any chance of one?

 

[Lime]

I'd cover it in lead and paint it with anti-burglar paint at regular intervals.

 

[ChrisD]

Thanks for the suggestions, I appreciate them all. The bay window was put in when that part of the house was used as a shop. Since it is part of the history (albeit recent) of the house and is generally sound, I don't have any desire to replace it. I am now considering the phrase "honest repair" while I decide on how best to proceed. The next job will, of course, be the re-pointing but I think I am going to have to wait until it warms up a bit - there is a lot do. It will be nice to get past this current season, the house looks a lot better when disguised by greenery - you can just see the older windows in the photo below - the bay is out of shot to the left. Pointing and other jobs-in-waiting hidden by green stuff.