Flat roof

DerbyBorn wrote in news:XnsA4529D79A3873TrainJPlantntlworldc@81.171.92.222:

Does this photo help a bit - see the white facia board.

I have something similar but at least I have run the downpipe from the pitched roof gutter to discharge into the gutter for the flat roof. Without this the localised heavy flow onto one part of the flat roof is likely to stress the flat roof covering unless perhaps it has been done with modern EPDM rubber which seems virtually indestructible if fitted properly.

Felt roofs need to be replaced about every 25 years because of UV, when was it last done, and how does it look know

In message , DerbyBorn writes

No. We had a flat roofed extension on our old house, no issue.

There is usually a question about flat roofs, it's along the lines of is the flat roof a certain percentage of the roof area, but it is a significant area

My insurers are only interested if the flat roof exceeds 25% of the total roof area.

We have a property where the entire roof is flat (asphalt, recently over-covered with 3 ply felt) had a couple of the "special offer" insurers say they were not interested in quoting because of the roof. Though interestingly those *same* underwriters were happy to quote if approached directly, although not at the "special offer" price, naturally :)

Our current policy document states that damage caused by (or to) a failed roof is covered, provided the cause is "sudden", though they clearly point out that damage due to wear and tear or lack of maintenance is not. Which is fairy snuff I guess. Best advice is budget for getting it recovered, if it doesn't need it now, it will likely do at some point...

Dunno about that but expect leaks sooner or later I'd say. Brian

In message , DerbyBorn writes

To add to what I said, which I think I misconstrued your question.

Our extension was a single story, but the house roof drained onto the flat roof via a drain pipe. Which was no problem (it had something over the roof felt in that area to take the flow of the water so it didn't damage the felt over time)

Insurers/mortage co not botherd

Sounds similar to here except the flat bit is about 40' x 12'.

For such a small area I'd be very surprised. There will no doubt be the universal get out clause that lets them off the hook for consequential damage if the fabric of the building is not properly maintained.

Flat roofs do need more maintenance than most other roofing types. The condition of it now is probably more of an issue than insurance/mortgages. How long has the current covering been there? What is the current covering? Is it getting towards End of Life?

IME of having some flat elements, insurance companies seem to work on the following thresholds:

I fall in the 20-30% depending on how you count it (with or without numerous bays, and I assumed it is quoted as plan-area, not surface area.

Oddly enough when you actually ask them to define their terms, they get really confused and wander off to the underwriters!

I must take a really accurate survey next time...

See if you can use the agent's floorplan or google maps to estimate the flat to overall roof area - or better still go and have a look with a tape measure.

I think that is a good summary and it sounds like the o/p is under 20% so no problem.

I've recently done a 2 layer fibreglass replacement cover on a 6sqm flat roof and while it was more difficult than I had envisaged[1], the result looks great and is absolutely bombproof.

In Edinburgh flat roofs are very common on tenements, this one is 1885 and middle is flat platform with slated flanks, guessing it was a cost thing, with slates visible from streetlevel for traditional look for buyers. was a buiding boom 1860-1890

For this one it was just refelted in layers of reinfiorced felt over cellotex insulation and on to the boards, the insulation allows the felt and boarding to expand and contract without racking off each other.

That's why you need to adjust the amount of catalyst added depending on temperature and mix in smaller quantities and / or also get spreading quickly to avoid exotherm

When you're already down at the minimum acceptable ratio (specified by the supplier) you are up against it though. I wasn't expecting the Indian summer we got when I was doing it in September and very strong sun was heating the deck to ridiculous temps but I had to get it done before the rain arrived. I have found out since that the supplier can provide a reduced speed catalyst for extreme temperature use. I'd recommend that DIYers buy the slow catalyst to give more working time for inexperienced hands. Tradesmen will likely work in pairs so they can work faster.