3 laters of felt vs single ply membrane (tectofin)

[Cej238]

Hello

My builder is offering me an upgrade (presumably) from a 3 ply felt covering for a 6.5x5.5m flat roof to a single ply membrane called tectofin. It will about an extra 3k.

When questioned he didnt seem particularly clear what the advantage was.

Ive als not foind much discussoon of the tectofin product.

Can anyone advise?

Thanks!

 

[^woody^]

It's a rubberised product similar to EPDM. You would need to look for accreditation with certain testing bodies such as the BBA - a "BBA Certificate", and want specific manufacturer performance and lifetime warranties.

I can't see any particular advantage for a domestic roof - certainly not £3k worth of advantage for the homeowner. It's a very niche system, and no real different in performance to other non-traditional membranes - EPDM, fibreglass, liquid plastic.

This would need specialist installation from trained accredited roofers, and not something a general builder would do, so these niche products tend to be promoted by builders who get a hefty kick-back from the local reps.

 

[Cej238]

Thanks - the quote I think is based on a smaller extension than we've ended up building - but assuming linear scaling with roof size it would be just over £3000.

3 ply felt seems pretty generic, we've not discussed other alternatives. Would you avoid 3 ply felt in favour of something else. We are sort of out of budget, so not looking for reasons to spend more money, but if there are alternatives at similar cost we'd be keen to explore.

Thanks!

 

[Mw Roofline]

My grandad bless him did the flat roof on top of our lounge over 30 years ago in mineral felt and it’s absolutely bang on even now.

I don’t think epdm/or the techno thingy is as good as my grandads roof.

 

[^woody^]

If MW's gramps is still around get a quote!

There is no reason that bitumen felt, done properly and maintained regularly should not last you 15/20 years or longer .... which is as long as almost all of the similar non-metal alternatives

The roof structure plays a big part, and proper falls with no dips and joists and decking that does not sag or move are important, as is the perimeter detailing as that's a common failure point.

If you are out of money, then if bitumen felt is within budget then no reason not to use that. Remember that most roofers are only specialist/interested in the system they know how to fit. So they will commonly say that their system is the best and all the other types are crap.

 

[bernardgreen]

For what it is worth....

A bitumen and felt roof that was designed to be permanently covered in a few inches of water lasted for 50 years without any signs of a leak. This was on architect Walter Segal's temporary house [url="https://www.theguardian.com/cities/...y-walter-segal-self-build-south-london-estate" ] click here [/url] Known as the Little House in the Garden, this temporary structure lasted over 50 years.

The layer of water prevents rapid changes of temperature which is the prime cause of failures in flat roof.

 

[Diver Fred]

How much is the quote for the Felt/bitumen roof? does it include the boarding?

I paid circa £1150 for a 22SqMtroof earlier this year in 3 layers of felt - last layer was 'torch on'. No boarding.

Neighbours fibreglass garage roof (18qMtr) done the month after cost circa £1300 including new boarding.

 

[Cej238]

Unfortunately, the 3 layers of felt option is part of the overall price. Rather the tectofin is an addon. I know that they bring in a separate contractor for it, but there is no 'refund'. Sounds like the felt option is fine provided it is laid right. Thanks for all the advice!