Which roofing felt?

[AndyDavis]

I'd like to replace all the felt on a pitch roof. Can anyone suggest the best (long lasting) felt around.

A friend suggested a two layer (underlay and felt) torch-on thing made by a company called Marley but he can't remember their names, are Marley any good and do the underlay and felt have a name? Is this the best way.

 

[Oskool]

What is the pitch of your roof?

If you go for the torch on felt the best performance to price ratio of Marley torch on felt would be their Quikflo range. It is a Elastomeric SBS Polyester based felt which is very easy to use.

Marley Quickflo Torch on felt comes in 16m x 1m x 2mm underlay, 8m x 1m x 4mm Sand underlay/toplayer and 8m x 1m x 4mm Mineral Cap in either green, blue, brown or black.

Look to pay about £29.00 plus vat for a roll.

 

[breezer]

thing i would ask,seeing as the origonal poster had not heard of marley, is this stuff very really really very easy to install, (including torch)

 

[masona]

I'd like to replace all the felt on a pitch roof. Can anyone suggest the best (long lasting) felt around.

You say you have a pitch roof with felt ? if so what wrong with using roof tiles ?
Roofing felts are only temporary from 10-15 years.

 

[AndyDavis]

Not sure what the pitch angle is (I'll have to climb up with my protractor first!) but it's a normal, post-war 3-bed semi.

The current felt, under the roof tiles, needs replacing because its gone in a couple of places and dangling in the loft in others. As the roof is going to be extended in one corner it seems a good time to do the work.

I had a look at the Marley site and they seem to have 2 or 3-layer system using an underlay, Top layer and cap sheet, I assume in that order. As theres roof tiles on the top do I still need to use all three coats?

 

[masona]

Ahhh you see, I thought you have a flat pitch roof with no roof tiles

I can't see what the problem is using the standard roofing felts, you don't need torch-on unless it's exposed to rain.

 

[phykell]

The current felt, under the roof tiles, needs replacing because its gone in a couple of places and dangling in the loft in others.

Interesting. So you have felt underneath the tiles? I've seen this before thinking it about it, but this is the first time I've thought about my own house's roof. It has slate tiles but there's definitely no felt under them. From my loft I can see the slates. Is this a problem?

 

[AndyDavis]

Sorry, didn't mean to confuse you. I thought they all had felt under the roof tiles. I assumed for insulation and sound/rain protection.

Are all the Marley stuff for roofs without tiles, or do they have one I can use. Alternatively should I get something from Screwfix?

 

[masona]

The roofing felt is protecting the rain entering into your building. Older property don't have them but it's not important.

If you have a broken roof tile, the rain falls onto the roofing felt and run down to the gutter saving you internal damage.

 

[Oskool]

Oh... pitched roof felt.

There are 3 main options for underslating/under tile felt:

1. A breather membrane - i.e. Dupont Tyvek, Klober Permo, Monarflex 700 - lets the your roof breathe, strong but expensive £80-£120 for a 75m2 roll.

2. A non breather - Dupont Eas1felt, Klober Spanflex, Marley Lite & Long - strong, often plastic but go for one with a fleece or absorbent backing to help hold the moisture longer to prevent dripping from condensation, you may need extra ventilation - £30-£40 for a 40-45m2 roll.

3. Traditional 1F felt – can tear, surprised it still has a British standard, bitumen with reinforcement, you may need extra ventilation. Upto £10 for a 15m roll.

If you need any roofing materials don’t go to screwfix, go to a roofing merchant like Asphaltic Roofing Supplies they supply nationwide and deal with the public and can give helpful advice if necessary.

 

[AndyDavis]

Thanks!

 

[AndyDavis]

I've just been told by the builder not to use any breathable membranes (I was intending to use Dupont Tyvek) because they disintegrate after about 5 years. He's suggested using a water proof, rubber like, non-cloth based felt instead. He said that I have a cold, vented loft so water and sunlight would get in and destroy the breathable membrane. I spoke with the Asphalitc people and they agreed that the Tyvek will disintegrate but only if its exposed to sunlight, they suggest using some eaves tape to cover it up.

Is it still a good idea to fit the breathable membrane, given that I'd like something that going to last and last. How long does the breathable stuff last?

 

[masona]

How long does the breathable stuff last?

Not sure, why not buy a good quality roofing felt using tiles vent and soffit vent and ridge vent for internal ventilation.

 

[Oskool]

Correctly installed Tyvek has a 30 year product warranty from Dupont.

Exposure to direct sunlight shouldn't exceed 6 months and don't dress the Tyvek into the gutter as in traditional methods. Use a plastic eaves carrier/support tray that replaces the underlay as the "drip" into the gutter.

 

[legs-akimbo]

I dont buy into the idea of expensive roof felts unless you are creating a warm roof a different issue entirely from your problem, buy the regular reinforced cheap as chips underslaters felt or the stronger longer plastic type (name of escapes me at the mo) which work out relatively the same price for overall coverage. The best and most inconspicuous ventillation are the continuous facia mounted vent strips and work perfectly well with the tried and tested regular slaters felts, if anything the new types of felts have added and not helped Some have proved problematic, and most builders that have used them are returning to to the traditional slaters felt. 22 years as a builder is speaking from experience... if you have money to burn then go the expensive route ,but there really is no need. Felt as mentioned in other posts is not the integral part of the roof covering it is merely an emergency barrier.