kingspan or sprayseal

[Fred]

Howdy,

apart from getting sashes back to working order and the odd strange plumbing job, I am also contemplating what to do with my loft insulation. Right now, there is a fourth bedroom in the loft that of course has never even heard of building regs. That aside, I suppose winter is around the corner and I don't want all this heat loss due to no insulation present.

I have a bit of experience with kingspan and would feel reasonably competent to kind of waste a weekend or two to sort it out myself. But this old roof is really windy. Every breeze just goes through and messes up with the loft storage area. It is currently so dirty that I would not want to store anything of use up there. Essentially, if it could go in storage there it could also be stored permanently on our local dump site! Also the roof itself has nail fatigue and what not and will certainly need regular roofing attention. In my experience, keeping these old roofes going costs about 250-300 per year.

In comes sprayseal (and warmroof and apparantly a few others) who offer to basically use foam to glue the roof in place and offer near perfect thermal insulation. Cost is going to be much higher than for a bit of kingspan, and I could save myself the, uh, diy weekends. They claim that their system makes reroofing redundant as they offer a

10/25 warranty. This sounds maybe too good to be true, sort out insulation, keep out the wind and forget about a new roof. I have noticed that other threads in here on insulation and what not have not mentioned these firms, which makes me suspicious. Any opinion on what course of action I should pursue?

Fred

[Dave Liquorice]

Personally I wouldn't have such work done. Far better to have the roof stripped, timbers replaced as required, a modern breathable sarking fitted, new treated battens and the tiles/slates put back assuming they are in good enough condition. Any flashing done in at least code

4 lead. You shouldn't have to worry about the roof again, the void will no longer be a wind tunnel and be clean.

It may also be worth thinking about the resale value. What is lurking behind that foam? The timbers can no longer dry out. You admit yourself that the roof is not in good condition and no sarking means that water *will* get blown in...

[Andy Hall]

Mmmm.

If you plan to stay in the property, get it re-roofed as soon as you can reasonably do so. A typical re-roof can reuse a proportion of the slates and then reclaimed ones are normally used to replace any that are too badly spalled.

The roof can be stripped, felted and battened and everything replaced in a few days. Lead valleys etc. can be replaced, the timebers properly inspected, treated and if need be parts replaced very easily. Then no more roof maintenance for a very long time.

It's going to cost you in the low £k but is by far the most sensible solution. On the very first house I bought I had this done and it both added to the sale price a couple of years later and made the house much easier to sell.

The foam spray solutions are a really bad idea for this application because the roof is already in poor repair and water can blow up under the slates. RIght now it can run down and out and if the odd drops end up in the loft not a lot happens. If you gum it all up with foam, there is no ventilation for the timbers to dry out and you are inviting rot to begin. If you are planning to stay in the house, you really don't want to face having to replace loads of rafters etc. in a few years time.....

If you are planning on moving in a couple of years then I would do nothing.

Personally, if I were viewing a house to buy and saw one of these gunge jobs, I would politely take my leave. No discussion.

As a temporary solution, you could put in some pieces of Kingspan just to provide some insulation, but I wouldn't do anyhting that reduces roof ventilation without doing a proper re-roofing job. It could be that the ventilation is keeping the timbers dry and preventing wet damage.

.andy

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[Dave Plowman (News)]

When you have a new roof done in the London area, they insist on ventilation being provided to the rafters etc. This is to keep them in good condition.

I don't see how a roof covered from the underneath in foam can fulfil this requirement. And apparently, most surveyors will mark down the value of a house so treated at sale time.

[Christian McArdle]

I'd avoid these spray-on solutions. Not only can they make it difficult to effect subsequent repairs, but by the time you've paid for them, you're half (or all) the way to getting a complete reroof. When this is done, you can specify a non-ventilated construction using breathable sarking membrane that will enable you to entirely fill between rafters with Kingspan. 75mm between with 25mm under will give you very good insulation. Then all you need is vapour check plasterboard and to block up any eaves ventilation.

Christian.

[IMM]

The best suggestion. Fit a warm roof and eliminate loft ventilation.

[Christian McArdle]

Technically, it isn't a warm roof solution unless the Kingspan goes on top of the rafters (perhaps with some between). 50mm on top and 50mm between should be enough for a loft conversion, although I haven't got the tables in front of me. This is only possible if you have a detached house and planning permission, as it affects the roof line. The problem is that you can't fully fill the rafters unless you have an equal thickness above them. You can't have 75mm between and 25mm above, for example.

I suppose you would call my original suggested solution a warm loft, cold roof.

Christian.

[Pete C]

Hi,

One way to stop wind blowing through the loft is stapled or batten a vapour permeable membrane like Tyvek Housewrap under the rafters.

How much of the loft is occupied by the bedroom? That will make some difference as to how best to insulate it.

cheers, Pete.

[Fred]

Thanks guys, for all the help. I am amazed by the quality of this group. Not that I agree with everything that is being said but the spam/flame to content ratio is very favourable indeed.

That being said, I would have thought that about 1/3 of the total loft area is converted, however, most of the remaining loft part is not high enough to allow to stand up.

Sooo, how best to approach so as not to have to much expenditure that is useless come reroofing time - we bought this house to stay, but nobody knows whether this is going to be true. We also bought on the peak of the market (moving with young children has certain constraints re term time) and we have no money left to pay for the reroof immediately.

Cheers, as ever,

Flurin

[IMM]

I have always wondered about this approach.

1. Would be be better to remove any felt with a Stanley knife, install Tyvek under the rafters in the loft and seal off the eves vents.

or

1. Leave the felt, install Tyvek under the rafers and right down sealing the eves vents.

Of course in both cases install a vapour barrier on the loft floor.

This way a gale will not blow through the loft and it will still be breathable.

[Christian McArdle]

Or even naughtier, rip out the felt, fully fill the depth of rafters with kingspan, with an additional 25mm below. Vapour check plasterboard and replace the felt with breathable membrane when reroofing. The two layers of kingspan (with joins very much not coincident) would act as sarking...

Don't tell the BCO!

Christian.

[IMM]

This way the tiles come off. May as well put 25mm x 25mm batons over the outside of the rafters to give a vent space so any vapour rising from the loft will get away, and batons counter to the rafters that hold the tiles. Then that is all legal and the BCO would not bat an eyelid.

[Pete C]

Hi,

Most economical way would be to insulate the unconverted part with rockwool roll to the top of the joists, and around the bedroom with thick rockwool batts. If the bedroom is hard up against the rafters slide some kingspan/celotex in the gap between rafters, roof and plasterboard.

If using tyvek/vpm under the rafters take to from the top down to just above the rockwool and try to tuck it in at the bottom so any water leaks go out under the eaves.

When you come to reroof the tyvek could be battened and give some weatherproofing to the loft while the roof is redone.

There may be an insulation grant available from your energy supplier, making it as cheap to have someone come in and do the rockwool stuff as fitting it yourself.

cheers, Pete.

[Christian McArdle]

The idea is that the tiles come off at your leisure, not at the time of initial slash and insulation...

Christian.

[IMM]

You would need to tape the Kingspsan to prevent any water entering the loft.

[Andy Hall]

Bu this leaves water hanging around the rafters. Is that such a good idea? .andy

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[IMM]

It was temporary in-loft fix. It would be fine if the tiles are fine. When replacing the tiles you baton properly and fit the Tyvek on the outside of the rafters.

[Andy Hall]

Except in this case we know that they are not. There is an ongoing annual maintenance due to rusted and failing nails and the OP is not able to do a re-roof yet.

Temporary fixes have a habit of lasting longer than intended.

I don't disagree there, but the idea of taping things up and restricting ventilation such that water can collect around the wood is not wise.

having once owned a house like this and originally in similar condition, I feel that it would be a far more practical and safer solution to put in some low cost fibre or Rockwool batts as has been suggested around the outside of the bedroom to at least keep that reasonably warm for now, and then to reuse or even throw it away when a proper job can be done to the roof.

.andy

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