Roof Insulation.

[Gary]

Workshop is a double garage and at the moment the roof is uninsulated and devoid of any plasterboard on the ceiling. Will this be suitable for insulation between the ceiling joists prior to plaster boarding?

 

[Dibs-h]

As long as you vent the roof space and don't block up the eaves so to speak - you should be ok.

 

[MikeG.]

Hmmmm........I'd be very careful with that stuff.

Polystyrene is incredibly dangerous in fires, so the only place I ever specify it is under concrete......and I don't even generally do that these days. Add the ghastly little bobbles that get everywhere when you are working with the stuff, and its extremely brittle nature, and I suggest you leave the stuff well alone.

It is a better insulant than mineral wool, but is less good than the PIR boards such as Kingspan and Celotex.....and they are what I would recommend.

Mike

 

[Dibs-h]

As long as you vent the roof space and don't block up the eaves so to speak - you should be ok.

Sorry - didn't notice the link to polystyrene. I once saw a Fire Brigade video of how that stuff burns on a ceiling - wouldn't touch it with a barge pole!

 

[Gary]

I thought as much. What am I looking at for the cost of 2400x1200x75 Kingspan?

 

[head clansman]

hi

as mike say don't touch it polystyrene is lethal when a fire starts hop it never does we underwent training years ago in the dockyards , i think from memory it's not the fire that kills you it's the toxic fumes i seem to remember life span about 2 Min's only and dead . hc

 

[Mattty]

I thought as much. What am I looking at for the cost of 2400x1200x75 Kingspan?

You should get it for around £25 to £30 per sheet. Ring a few places. Most merchants will barter a good price at the moment. This firm used to be cheaper but i haven't used them for a few years.-
http://www.secondsandco.co.uk/?gclid=CP ... 4wod3Tlo3Q

 

[crazylilting]

I have a sloped tin roof and want to insulate it. When it rains it is so noisy. Can you just glue kingspan to the tin? It is corrugated so there will be some air spaces running from one end to the other but will that be enough? How thick should the insulation be? It's a fair size roof 20 x 34 so it could get quite costly. It doesn't have to stay room temperature in the shop but i don't want to be freezing in there either. I missed a good deal on some seconds that was 2 inches thick but am keeping my eye's open.

The other question is about foil back or not? and what glue to put it up onto the tin if in fact it is a good idea to glue it directly to the tin.

 

[Dibs-h]

what's the tin "sitting" on?

 

[crazylilting]

Not much of anything really. the outside walls and three beams that run the length of the shop, which are supported by three I beams running the width of the shop.

 

[Dibs-h]

In that case why not just screw Kingspan sheets to the underside of the 3 wooden beams that the tin sits on? No glueing etc.

 

[MikeG.]

Dibs,

those will be purlins, and they will be way too far apart to take the insulation boards.

Mike

 

[crazylilting]

those will be purlins, and they will be way too far apart to take the insulation boards.

That's right, they are about 7 feet apart, that's why i was wondering if i could glue it to the tin itself. I thought about spray insulation but it would be about £1000 to do it all and with all the machinery in there it would be to much mess.

I'm going to be running some heating lines and pop in a few radiators from the house so want to get some insulation in there pretty soon, so i'm looking for some ideas.

 

[Dibs-h]

Dibs,

those will be purlins, and they will be way too far apart to take the insulation boards.

Mike

I see what you mean. Couldn't he fit 3"x2" joists to the underside of the purlins or even 2"x2" ones and then screw the kingspan to the "ceiling joists" (at 90 degress to the purlins)? Be a little work but much less hassle (to me anyway) than messing about with the spray stuff, or even glueing the kingspan to the underside of the tin.

For a 7' span - i would assume (without looking at the span tables) that 3"x2" would be fine, perhaps even get away with 2"x2".

 

[crazylilting]

How hard is it to glue to the tin? Or can it even be done? These are the questions?

I need to know if the the upper corrugations will be enough ventilation? It looks like this http://www.austinlaz.com/images/rSheets_big.jpg

Has anyone ever glued it? What kind of glue did they use?

I really don't want to frame it unless i'm going to frame it for doing a green roof which i also considered. A living roof makes a lot of sense. Provides insulation, sound protection. But seems like a lot of work and have to put a membrane on the tin (aluminum) as well as something to keep the dirt etc. on the roof. There are definitely some good views from up there so this is an option but i think one for next year.

I need some thing quick and cheap for now. Any ideas would be appreciated

 

[MikeG.]

Crazylilting,

I have never heard of gluing sheets of insulation to the underside of a tin roof, and can't think how you would do it successfully.

I would advise a great deal of caution about your living roof proposal. For a start, they are enormously heavy, and your roof structure is clearly designed for a lightweight covering only. You will end up with problems if you don't beef up the structure a lot.

Additionally, soil is a relativley poor insulant (compared with, say, Kingspan). It is difficult to retain on the roof, creates big problems in getting the water properly off the roof without filling up the drains with silt, and finally, it is very difficult to get anything attractive to grow on the roof. They usually end up (very quickly, actually) as a brown, weedy mess, with most of the vegetation dead.

I have been involved in a number of "green rooves" over the years, and am actually designing one at the moment. My view is that they are an expensive failure, and are a bit of a green fashion item.

Be very cautious!

Mike

 

[crazylilting]

Thanks for your reply Mike.

I may have to experiment a bit then, if you haven't heard of it. I'll get some foil back and give it a go. Worse comes to worse i'll have to frame something up.