Flat roof question.

I find it mildly curious that in the 21st century, no one has seen fit to come up with something that can be poured, finds the crack and seals it ...

I have done just that with Isoflex liquid rubber. Leaked at the junction between my and my neighbour's garage roofs, bitumen felted. Must have been quite a big crack as it took quite a lot, and at one point appeared dribbling down the inside of the garage wall. Sealed the leak though.

It's already had that treatment. But same as paint, doesn't last forever.

Had ours fibre glassed about 10 years ago. New OSB boards, the old torch-on felt had failed and knackered those boards. Took the oportunity to fit 100 mm of celotext between the roof joists. The fibre glass is still waterproof or at least if it is leaking it's not getting to anywhere visible inside. But then there is a poly sheet on the warm side of the insulation and up and over the joists...

Here you go, Dave. Don't say I never do anything for you:

Big snag is actually knowing how long these 'new' methods do last. Plenty claims, though. The decking is marine ply, so hoping it will still be just fine. The chippie who did the work was very good indeed.

Glassfibe will be quite a bit more expensive than EPDM. Probably best to find a roofer who can provide quotes.

I don't think any special tools are needed to install EPDM, so it may be suitable for DIY, though you may need several people to handle the weight. It took 1 day to reroof a double garage with EPDM including changing some boarding and maybe a joinst.

How about old fashioned lead ?

Sounds like the story of the salesman who turned up at Steinway pianos saying "We've got this wonderful new material for piano hammers instead of that old fashioned felt." Steinway said they try it out. "Ah, when should I come back?" "In about 100 years."

Doesn't help indoor FM radio reception.

Sometime in the 1970s I was involved in a submarine cable project. Featuring Germanium transistors "Silicon hasn't been around long enough to know they will last"

Asked my oncologist "what is the 15 years outlook for this chemotherapy?" "Dunno: it's only been around just over a decade"

EPDM & fibreglass are both diyable. The issue we ran into with EPDM is that it's not compatible with bitumen, so every bit of boarding must be strippe d off & renewed.

Lead is a foolish idea these days, even in apparently inaccessible places. Copper even more so. Many swear by steel, but it gets ugly in time.

In the end we left the old felt in place & used bedsheet, bitumen & sand. C rude for sure, but it was a very quick job costing almost £20 somethin g and last time I looked was still in good nick years later. If/when it det eriorates, more cloth & bitumen is only another £20.

NT

I've been using EDPM, went on a one day course to learn how to do the corners.

It's easy to repair with its special primer and glues and patches, like when i dropped a slate on it.

Made by firestone , Ultra violet resistant.

Normal shed roofing only lasts a few years. Lead has to have gaps for expansion where nwater dirt and ice get in.

And while youre at it add loads of insulation under it.

I did OSB3, then kingspan attached with foam, then OSB3, then EDPM

George

Did my garage/kitchen/porch about 12 years ago.

Why two decks?

First OSB3 was 18mm for the structure, on top of beams. Then a 2 layers of kingspan attached with foam then thinnner osb3 foamed on it (no screws or cold bridging, and makes roof walkable) then glued EDPM onto it.

I am glad that it is easy to repair as it looks like it might be easily damaged.

which would ned to well above the new "earth"

For a flat roof on a double garage the quote was £2100+ vat for EPDM, part of one joist and removal of old material.

EDPM stuck to OSB is tough stuff, I broke mine by a slate sliding from high up the roof and spearing it with a point