Is this sensible?

[SammyQ]

Totally understand- even with the limited exposure (!) I've had in my new playpen. I reckon on building an insulated box within a garage to cope, but the pocket is limited. So it time with family issues!
Sam

 

[Hornbeam]

There are 2 approaches to insulating this type of building. If you insulate internally then you will lose space an detailing can be difficult. The alternative which is standard on many industrial buildings is to overclad. To do this you fist lay an air tightness membrane over the roof/walls and then install a spacer bar and bracket system to create a cavity for mineral wool insulation. Install insulation and then sheet over the top. Will be much more expensive than under insulating but guarantees a good job, improved aesthetic and weather tightness.
Lots more work but I have worked in metal roofing for 20 years so only a small job
Ian

 

[SammyQ]

Thanks Ian; I did something similar to that with my previous home. 9" solid Belfast brick walls, no cavity, no space for internal insulation without severe compromise in existing spaces. I wrapped the building in Celotex 8'x4' batts between battens, then over laid twinwall, held in place by 1"x 5" PAR, to mimic half-timbering. Worked an absolute treat. Living spaces became much more comfortable - and quieter!
That approach is not viable here, for aesthetic and financial reasons, so I am concentrating on delivering what you might call " minimal lining " to optimise space and outlay.
Just been out with a tape and I am optimistic I can adopt MikeG's approach of peaked internal insulation, supported by some timbering.

Thanks again, Sam.£

 

[Woody2Shoes]

Just a quick thought re. asbestos sheets - a couple of years ago I got some tested by a local specialist firm and it cost me about £80+VAT - I gained peace of mind and, on their advice, was able to dispose of it by carefully double-wrapping in DPM and taking it to the council tip (I think councils are becoming less ready to accept this stuff lately).

Most of the sheets used as cladding are fairly unlikely to contain the really nasty 'blue' asbestos (I have seen this used as pipe insulation etc. however) but it's not worth taking chances - and leaving the stuff in situ is very often the most sensible option.

No dust is good to breathe, so sensible precautions are always worthwhile.

Cheers, W2S

 

[SammyQ]

Thanks W2S, we concur, I think. My sheets (sic!) are in good nick and my plan is to leave them alone, isolate the inner surface behind physical barrier (Kingspan yada yada) so that dust cannot reach my working space. Outside, I intend to do nowt, save not drink from the water butt that fills from this roof....
I've been out today, measuring and cogitating in between falling over pineapple dammed pineappling boxes of pineapple, so I hope to outstrip Baldrick by teatime.
Sam - in the blue haze....

 

[TomGW]

This doesn't seem to have been suggested but, in this instance, I would seriously consider getting the inside of the structure (walls and roof) sealed with a spray-on insulation. This would seal the 'asbestos' sheeting, if that's what it is, and provide a fully insulated box.
This would result in a 'hot roof' and 'hot' walls, where ventilation gaps are not needed.
Very simply, a 'hot roof' is a construction which has only two 'air' surfaces - one on the inside of the building (the ceiling) and the other on the outside of the roof covering. Consequently there is no 'cold' surface (for cold read colder) anywhere, which would cause warm, moist air to cool and allow condensation to form. The inner ceiling will be the same temperature as the air inside and the outer surface will also be at the air temperature - result; no condensation.

 

[SammyQ]

Thanks Tom; between yourself and Mike earlier, my fuzzy naivety (ignorance) of 'hot roofs ' is now cleared up. I'll look into it and price it up once I get time. Christmas - and unexpected rising damp - are front and centre presently. Up to now, I had considered a box of Kingspan inside the pre-fab concrete box, but a 'wee man ' with his gear doing what you suggest would be a lot less work and oodles faster! It will boil down to cost and R or U values.
Cheers, Sam

 

[Lons]

Thanks Tom; between yourself and Mike earlier, my fuzzy naivety (ignorance) of 'hot roofs ' is now cleared up. I'll look into it and price it up once I get time. Christmas - and unexpected rising damp - are front and centre presently. Up to now, I had considered a box of Kingspan inside the pre-fab concrete box, but a 'wee man ' with his gear doing what you suggest would be a lot less work and oodles faster! It will boil down to cost and R or U values.
Cheers, Sam

Can be a good solution but when we had it done to a grade 2 listed stable conversion a number of years ago it was bloody expensive. Yours is just a small building though so might be worth the effort. It doesn't give a flat surface as it's sprayed on so you need to decide if that's an issue

I can't remember who we used but was a local company around Newcastle.

Hope you enjoy Alnwick, it's a lovely town despite the parking issues, I'm 6 miles North of Morpeth btw.

Bob

 

[SammyQ]

Thanks Bob; I haven't forgotten your invite, just trying to sort out some hidden problems that only manifested themselves AFTER we bought the place...
I suspected that this spraying insulation might be the most expensive option, and the lumpy texture isn't too attractive either. A compromise may be to coat the roof only, and 'kingspan ' the rest. Only trouble is, I suspect operators charge highly to just get their kit on site, then actual quantity is relatively cheap. That is certainly how carpet cleaners cost their services. We'll see.
Sam