What breathable felt underneath clay tiled pitched roof?

[David Angel]

I have a small, clay tiled, pitched roofed outbuilding and the felt underneath is shot. Some of the tiles have also seen better days.

1) I see forum recommendations of a breathable felt called 'Dupont Tyvek'. Can someone confirm that the website below has the correct stuff? It appears that it is called Tyvek Supro.

http://www.breathermembranes.co.uk/epages/Store2.sf/?ObjectPath=/Shops/Store2.Shop1509/Products/un102

2) To re-roof, is it as simple as :
- Remove all tiles (and remove lime motor holding top tiles)
- Remove the horizontal battons
- Take the old felt up
- Put the new felt down (and leave overhang at the bottom for guttering)
- Replace with new battons
- Replace tiles + remorter the top ones back in with lime

3) I need to replace some of the tiles (approx 50%). They look like a fairly standard affair curvy clay tile as seen on old properties. Should I first look for reclaimed ones? Or is it best to buy new hand made ones? Can someone point me in the right direction online for new ones?

Thank you in advance for any advice you can give.

 

[Mark]

DuPont is the maker, Tyvek is the product brand name, I would guess that Supra is an 'improved' spec.

In theory roofing (at least in terms of tiles/underlay) is fairly simple - but complicated by being 10 yards up! Issues about how you handle edges, flashing etc

it is deceptive that many tiles look almost exactly the same but dont actually quite sit well together when you mix them.

 

[Geoff Flegg]

Just had my roof re-done - the roofer swore by Proctor Roofshield as a membrane (breathable felt replacement). It's an opinion of one, there are many other products out there.

http://www.proctorgroup.com/

I believe it was about £90 a roll - he also used some cheaper £60 a roll membrane as temporary covering. It was really noticeable that the Proctor product was much stronger and tear-resistant.

He also put a strip of a very heavy non-breathable felt (intended for flat roofing) at the bottom of the pitch - so this is what drapes into the gutters. Very durable, and also not bright green (which the roofshield is!)

Broadly speaking, your re-roofing description is right, but of course can be complicated by lead work, rooflights, finding rotten timbers etc etc.

Beware that sometiles tiles can look OK until you disturb them - at which point they crumble. 50% shot sounds quite high to me, and as Mark says you may have problems matching the profile.

 

[inwood]

Note that if you go for Tyvek it is not UV resistant so you will need something to carry the water into your drainage - avoiding having the tyvek draped into the drainage and exposed to the sun. They are generally referred to as eaves carriers - bits of plastic effectively that sit at the bottom of your rafters, under the Tyvek and continue over the eaves into your drainage, thereby protecting the membrane.

Dupont's version can be found at:
http://www2.dupont.com/Tyvek_Construction/en_GB/products/accessories/accessories2/eaves_carrier.html

Or most roofing suppliers will undoubtedly have a cheaper version.