slate roof - felt or not?

[fred]

In article , George (dicegeorge) writes

Oooh, that is a lot.

The benefit of boarding and the use of breathable membrane is that it leaves your options open to do absolutely anything underneath in the future. You've clearly got some dormer and used attic space so the option of a warm roof is useful and the small additional cost over a basic job should be worth it.

I'm used to seeing roofs in relatively exposed situations so would automatically tend towards boarding, felting/membraning, battening, counter battening and finishing. Although possibly with variations depending on the final roof finishing. I wouldn't like to see membrane flapping loose over rafters.

[Mark]

Well that does rather depend on the size of the roof, with the cost of real wood and labour these days it could add considerably to the cost.

I built that roof in 1971 at the tender age of 26 I think the material cost was about £300 for the wood and it was done without any electric tools just a hammer and handsaw. :)

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[meow2222]

How much rotten woodwork? Again its usually way less work and cost to simply patch the bad wood. A handful of added bits of wood versus a complete reroof... or is the roof really at risk of coming down on its own?

If you reroof, felt is a requirement.

right - do make you future life easier though, as others have said.

Fun :( Maybe you need one of these... :)

[Hugo Nebula]

On Mon, 28 Apr 2008 22:42:56 +0100, a particular chimpanzee, The Natural Philosopher randomly hit the keyboard and produced:

A "warm roof" is insulated above the rafters and therefore doesn't need venting (the rafters are held above the dewpoint). Any other roof is a "cold roof" despite the advertising of the breather membrane manufacturers.

The void between the insulation and the covering in a cold roof must be ventilated in some way. If vented through gaps at the eaves and the ridge any membrane can be used (slater's felt or breather membrane), otherwise breathable membrane must be used in accordance with the BBA certificate (taut & counterbattens over or draped, laps taped or open, etc).

[The Natural Philosopher]

Yes.

Yes ;-)

[The Natural Philosopher]

I heartily agree. A good sound roof is with a lot in terms of peace of mind, and 50 years down the line, resale value.

It MAY even net you a bit less insurance costs.

[The Natural Philosopher]

Thats a very moot point: I would say that if more than about 15% of wood needs repalcing, its probably ceheaper to strip and replace everything suspect. I could NOT elieve how much time it took a carpenter to make a bit of dormer.Essentially all the fiddling on the dormers took MORE time than putting up all the main roof timbers.

I would only ver patch repair in a listed situation: if any part of a joist is gone, take the whole joist out. Its haboring spores, and its suspect, and it tales just as long to cut in a section as a whole new joist.

I certainly believed it was.