Flat or slightly sloping roof question

Jul 08, 2016 18 Replies

Looking at replacing a small flat roof on an extension (thread a couple of months ago).



Expected cost around £1k.



I was looking at the powder coated steel roof of our shed the other day and thinking that it was looking pretty good 3 years or more on.



I know that this is not a traditional finish for a flat roof on a domestic property, but is there any other reason not to?



Cheers


Dave R


If it were me, I'd consider zinc or aluminium.

Noise? ether when it rains, or possible annoying clicky noises when it expands/contracts ...

Is that not going to generate a lot of noise when it rains? Brian

It works well. But eventually it'll be a rusting eyesore.

NT

Many years ago when I lived in Australia :-( some houses had "tin" roofs. Apparently when it rained the noise was awful.

I lived in a tin roofed converted garden shed in S Africa. When it hailed, which it did, often, it was deafening.

Mind you it wasn't insulated either.

I assume that insulation, joists & ceiling would much reduce the noise.

NT

We have a powder coated steel roof on our house extension (specialist roofing from Tata Steel) but this is designed to look like a zinc roof. It is a number of sheets with crimped joints. Looks pretty good.

It isn't particularly noisy in heavy rain because it is laid on wooden sheets (can't now remember if they were OSB or chip board) designed for roofing.

Under that is a significant amount of Celotex (or similar) to modern building regs.

However here I am looking at the corrugated (square section) roofing more commonly used in agricultural buildings.

It won't look pretty, but it should be durable. Possibly as durable as torch on felt.

It has just occurred to me that if it does get worn out (or at least rusty) then all you have to do is unscrew the bolts and bolt new metal sheeting in place.

Just idly toying with the idea at the moment, but it could be an interesting option.

Cheers

Dave R

Yes - that's unlikely to be much different to a felt roof as the mass of the board stops it resonating as well as attenuating the noise. As will the plasterboard ceiling.

Steel sheets with no boarding are likely a different matter.

There is a similar alternative made out of zinc. Expensive.

Made up for, no doubt, by the fact it was raining.

The tin has several inches of insulation under it. The major problem is pre serving the weather seal at joints. Tin flexes in violent winds and expands and contracts a lot more than stone or clay. Large sheets being both a ble ssing and a downfall. I imagine going around the finished product with a so ldering iron might be the only way to cure that.

Wouldn't the solder tend to come away from the steel when flexing occurred on hot sunny days?

I recently had a shed roof [Corrougated Steel] replaced, one of the items charged for that was not included with the original was a tub of grease. This it turns out was to lubricate the overlapping flashing that covers the wall/ roof at the edges that don't drain.

Not sure how long it lasts though and I dont see any grease noipples anywhere for the service :-(

AB

If you want your nipples greased, you need someone other than a tradesman ;-)

preserving the weather seal at joints. Tin flexes in violent winds and exp ands and contracts a lot more than stone or clay. Large sheets being both a blessing and a downfall. I imagine going around the finished product with a soldering iron might be the only way to cure that.

d on hot sunny days?

Like the sealant strips always do you mean?

Dunno, I have tiles.

On Saturday, 9 July 2016 22:08:04 UTC+1, Archibald Tarquin Blenkinsopp wro te:

s preserving the weather seal at joints. Tin flexes in violent winds and ex pands and contracts a lot more than stone or clay. Large sheets being both a blessing and a downfall. I imagine going around the finished product with a soldering iron might be the only way to cure that.

ed on hot sunny days?

Would it have been to allow movement as things expand and contract?

Zinc reacts with sunlight so they used to paint the roof after putting it o n. It comes ready treated these days. Why would they use a metal flashing t hat could rust?

Yes it is, I think the flat stuff is aluminum. It is bent over the wall and continues down it for about 400mm. Around a metre lies on the corrugate. The corrugate was cemented to the wall around half a block from the top. I suspect that the new corrugate is no longer fixed to the wall as that was the point where it rusted. I will ask the person that did the repair as it is around two years since the work was done and in the warm weather there is the occasional clang from the roof.

The flashing doesn't rust. Sorry I didn't make things clear.

I think the corrugate was treated, most of it was in perfect condition. Only the bits close to the cement bridging the corrugate and wall were rusted.

AB

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