Slate Roof With No Underfelt - A Problem??

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If a terraced house had a slate roof with no underfelt, would this be something that most people would want fixed immediately i.e. taking off all the slates, and installing underfelt and replacing all the slates again.
Or is having no underfelt on a roof not a major problem, and something which can be lived with i.e. not usually considered an "urgent" problem.
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SuzySue wrote:

In my experience, this is perfectly usual in older houses and doesn't constitute a problem at all.
Nick
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SuzySue wrote:

Our roof (1930s) isn't felted. It's not a problem except where there are gaps in the slates. When we replace the roof (probably this year) we will felt it.
--
Grunff

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Hopefully with a breathable membrane and not 'felt' (old-fashioned?)

--
Andrew

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Well it's not been urgent all these years has it?!
Providing the roof is intact and straight consider a foam type under tile job. That will insulate and hold everything in place BUT is a bitch if you ever do need to remove a slate cos it effectively glues them all together.
writes

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something
are
Our new (to us, built 1880) house doesn't have felt, and others in the same street have had problems after felting theirs due to lack of ventilation to the roof members. one thing about not having felt is there's plenty of space for air to get in and dry things out. If the house was built without one, just keep an eye out for missing tiles in high winds. If it originally had one though, I'd be inclined to get it re-felted pretty quickly.
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Dont even think about it.
Regards, NT
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tile
you
together.
Why not?
I used it on a property and not only did it save me a load of time and money it also saved the roof!
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For a short time, possibly. But removing ventilation from the rafters etc will almost certainly cause long term problems. It also prevents easy inspection for leaks.
--
*There are 3 kinds of people: those who can count & those who can't.

Dave Plowman snipped-for-privacy@argonet.co.uk London SW 12
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On Fri, 16 Jan 2004 09:29:36 -0000, PJO wrote:

Well you quote one reason yourself, when (not if) the roof needs repairing it won't be a straight forward job and you won't be able to reuse any of the slates.
The of course when (not if) water does penetrate the slates it can't dry out quickly and thus increases the chances that the rafters and/or laths are going to rot.

In the short term, yes. But when the roof finally fails it will be a much bigger and longer job thus more expensive.
--
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i've had spray foam on mine now for 10 years and it is fine. no more slipped tiles, a very warm useable roof space reduced heating costs and no condensation that people that don't know scare people with.
Dave Liquorice wrote:

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wrote:

I hope you don't ever want to sell it........ .andy
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So in another few years be prepared for *total* replacement of the entire roof structure - or if you sell, a survey giving a negative report.
Roof timbers *need* to be ventilated on all sides - if you look at a new roof you'll see ventilators fitted. Older roofs will allow enough airflow without.
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wrote:

I'm not about to be persuaded that spraying roof timbers with foam is a good idea, but the key reason roof spaces are ventilated is because the insulation is at ceiling level, the roof space is therefore very cold and condensation on the timber is likely without adequate ventilation. If you move the insulation to rafter level the air in the loft space is that much warmer and the risk of condensation substantially reduced.
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But increased on those parts of the rafters etc above the foam?
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Dave Plowman snipped-for-privacy@argonet.co.uk London SW 12
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Yes. Slate roofs are not watertight, the beams will get wet, and water will stay there. That would be a worrying scenario.
Regards, NT
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SuzySue wrote:

It is certainly not unusual to get roofs like this, especially in the North. The consensus seems to be that the lack of weatherproofness is offset by the excellent ventilation (which quickly dries out any water or snow that does blow in)! The roof space will also be pretty dirty.
I would say that if the roof looks in good condition (i.e. no broken or displaced slates, no rotten or broken timbers) then this is not a major problem. If you do need it doing, it is not normally hugely expensive (maybe a couple of thousand pounds?). tony
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On 7 Jan 2004 23:52:24 -0800, snipped-for-privacy@postmaster.co.uk (SuzySue) wrote:

It's very common indeed in older properties and is not a problem in itself. Having felt provides a second line of defence in case a slips out of place. Not having it means that you need to be a bit more vigilant with keeping an eye on the roof from the outside and the inside, since a slipped slate may mean water starting to come in. Even then, if it is only one slate, the overlapping of the slates would mean that that is not usually a major issue for a few days until it can be fixed.
If the roof is in generally good condition, then it is reasonable to leave it alone. On the other hand if the slates appear crumbly at the edges or if you experience a lot of them slipping because the nails have rusted, then it can make sense to have the roof relaid. This involves taking the lot off, and the battens and then laying felt, battens, probably re-using some slates and replacing others with second hand good slates.
I would see what happens over the course of a year or so and then decide. Obviously if there are any signs of water coming in or slipped slates, these should be fixed.
.andy
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     snipped-for-privacy@postmaster.co.uk (SuzySue) writes:

No. It's something you would address if you needed to refit the slates for some other reason though.

Houses designed and built that way have survived hundreds of years, so of itself, it can't be considered "urgent". Repairing a leaking roof would be urgent though, e.g. if an unlined roof has misaligned or missing slates.
--
Andrew Gabriel

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On 7 Jan 2004 23:52:24 -0800, SuzySue wrote:

If the slates are in good condition and well fixed then it's not a problem at all. Once a slate slips though it needs to be attended to with rather more urgency than on a roof with sarking.
Without sarking the roof space will probably be dirtier as windblown atmospheric fallout (dust) will find it's way in. Stored items will need dust sheets over them.
--
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