Attic insulation

laugh

Hey all,

Looking at the attached image how would you insulate that roof to give maximum headroom?

Some kinds of kinspan sheeting? Is there a barrier material to go on the inside or outside of the insulation?

The attic is designed to be converted with no timbers passing through the standing area.



roof.jpg

Prenderb

Is the attic floor already insulated? If not, I'd start there. I don't know how much there is to gain from insulating the roof if you have the attic floor already insulated - there should be ventilation within the attic space anyway which would kinda negate the effort of insulating the roof...

laugh

Prenderb wrote: »

Is the attic floor already insulated? If not, I'd start there. I don't know how much there is to gain from insulating the roof if you have the attic floor already insulated - there should be ventilation within the attic space anyway which would kinda negate the effort of insulating the roof...

I have the floor insulated, sorry I want to have a room up there for gym stuff and pool table.

paddy147

laugh wrote: »

I have the floor insulated, sorry I want to have a room up there for gym stuff and pool table.

You want a pool table and a gym in your attic?


So,have you checked out the celing joists sizes and their load bearing capacity with regards to added weight of a floored area and gym equipement on the joists themselves??

laugh

paddy147 wrote: »

You want a pool table and a gym in your attic?


So,have you checked out the celing joists sizes and their load bearing capacity with regards to added weight of a floored area and gym equipement on the joists themselves??

All the internal walls are solid block, and bear the existing joists, I'm going to put in extra joists in the area where the pool table is going.

Anybody know how best to insulate an attic at the roof?

paddy147

laugh wrote: »

Anybody know how best to insulate an attic at the roof?

Yes.

Can be shaved down to suit,if slabbing out the attic wuith plasterboard.

Im my case,both my attics are only for storing a few boxes and the Christmass trees.

Guinness69

How about this http://www.youtube.com/watch?v=h5mNKS6riVc&feature=player_embedded#!

I'm thinking of getting them as near my house. Looking for a quote from them in morning.

Guinness69

How much did they charge. What area was it. Looks like a top job by them. Well done

inchicoregirl

Is there any point insulating the attic floor and the rafters if you're only going to use the space for storage?
I was going to just do the floor.

fleet

If that's just rafter > felt > tile then you'll need to leave a 50mm air gap running all the way from the eve to the ridge and back down to the other eve.

We used multilayer SF40 foil stapled on to the rafter (with gun), batons and then plasterboard.

Guinness69

I'm doing the rafters and leaving the floor. I think the rafter job is best. If you do the floor and do a good job you will have your water tank or the pipes freeze if they are not protected really well as no heat from the house will get up to keep them from freezing. I live in a dormer and nearly the whole attic is living space. I have space to get in behind the upstairs walls so I am in fact doing half the house by doing this job. I think it will pay for itself in no time. The guy is coming out to price the job today. I'll update this as we go along. I'm thinking it will cost about €2500. I use to use oil that only had one setting, on full power. The house is 70's and freezing in winter boiling in summer. I since got in bulk gas and have the house zoned for heating with controls for each room. I use to believe it or not use 3500ltrs of oil to heat it. With the gas which we put in at Christmas last I have had 2 fills so far. I think with this job in place I will save one fill a year easily. A fill of gas is about €650.

Tabnabs

OP, I'm doing a similar job and for simplicities sake have decided to use Kingspan TP10 panels. Expensive to buy, but they're 2400mm x 1200mm so a few panels goes along way.

Details here
http://www.insulation.kingspan.com/ireland/tp10.htm

laugh

paddy147 wrote: »

Yes.

Can be shaved down to suit,if slabbing out the attic wuith plasterboard.

Im my case,both my attics are only for storing a few boxes and the Christmass trees.

Feck that looks like some job, the kinda thing that Canadian guy does on tv. I want to finish the inside to a ceiling though.

I guess that black plastic you have allows air get from the eaves to the ridge?

laugh

fleet wrote: »

If that's just rafter > felt > tile then you'll need to leave a 50mm air gap running all the way from the eve to the ridge and back down to the other eve.

We used multilayer SF40 foil stapled on to the rafter (with gun), batons and then plasterboard.

So just this foil on it's own?

Tabnabs wrote: »

OP, I'm doing a similar job and for simplicities sake have decided to use Kingspan TP10 panels. Expensive to buy, but they're 2400mm x 1200mm so a few panels goes along way.

Details here
http://www.insulation.kingspan.com/ireland/tp10.htm

Are you putting the panels on top or between the rafters? Leaving a gap between the felt and the inside of the board if between? Any fabric/membrane need to go on the outside of it?

laugh

Guinness69 wrote: »

I'm doing the rafters and leaving the floor. I think the rafter job is best. If you do the floor and do a good job you will have your water tank or the pipes freeze if they are not protected really well as no heat from the house will get up to keep them from freezing. I live in a dormer and nearly the whole attic is living space. I have space to get in behind the upstairs walls so I am in fact doing half the house by doing this job. I think it will pay for itself in no time. The guy is coming out to price the job today. I'll update this as we go along. I'm thinking it will cost about €2500. I use to use oil that only had one setting, on full power. The house is 70's and freezing in winter boiling in summer. I since got in bulk gas and have the house zoned for heating with controls for each room. I use to believe it or not use 3500ltrs of oil to heat it. With the gas which we put in at Christmas last I have had 2 fills so far. I think with this job in place I will save one fill a year easily. A fill of gas is about €650.

Sorry for not multi-posting all of this properly.

I had that problem in November/December, I put 8 inch insulation between the joists and everything froze, many hours spent with a hair-dryer getting the water going . . .

But If I insulate now at the rafters both together should do a great job and keep down the noise heard below when I start using the upstairs.

Guinness69

Well got my quote. 150mm thick biofoam 800. €5000 after a haggle. asked the guy how many sq feet I was covering. He told me he priced by cubic meter of foam. I asked how many cubic meters and he said we don't give that out. He said each co has different ways of pricing. I reckon the house is 2200 sq feet. but a lot of it is attic with crawl space down each side of the house. I got a quote of 4800 for kingspan down the sides with whatever (can't remember) on the flat part of the roof overhead. He gave me a quote for foam out level with the rafters of €4500 both quotes were with the vent plastic put in. Also the gable ends of the attic done too. It's not cheap but I know it will make a big difference to the heating bills.

Tabnabs

laugh wrote: »

Are you putting the panels on top or between the rafters? Leaving a gap between the felt and the inside of the board if between? Any fabric/membrane need to go on the outside of it?

Between the rafters. They are 95mm deep, so a 50mm panel will leave a 45mm gap (close enough to the 50mm recommended) to allow for ventilation. You will still get a cold bridge across the rafters, so when I get the finances back in order I will use the K18 insulated dry lining boards underneath to give a good finish.

The K10 panels are simply sawn a couple of mm larger than the rafter span and gently but firmly pressed into place. As long as the bottom of the panel is flush with the rafter, you know for sure that the ventilation gap is being maintained.

paddy147

laugh wrote: »

Feck that looks like some job, the kinda thing that Canadian guy does on tv. I want to finish the inside to a ceiling though.

I guess that black plastic you have allows air get from the eaves to the ridge?

Thanks.:)

The finish can be cut very smooth to allow for slabbing out of an attic space,I just chose not to have it done,as my attic space/height isnt big enough for an attic conversion,so I asked the lads just to leave the spray foam as is.

The heat comming out of the attic when the lads were spraying it in was unreal,the smell is very strong for about a day or 2,but the smell soon fades way after that.

I also had parts of the bedroom/bathroom and ensuite floors spray foamed,as my house was designed and built with an RSJ cantilever/overhang on the side of the house,so we sprayfoamed all of the 1st floor area where the overhang is.

The reduction in cold and noise from the overhang area is like night and day,since it was sprayfoamed.

I then insulated the rest of the floor area with 100mm Rockwool flexi slab and then installed Knauf 170mm insulation over that.Brilliant for heat retention and also accoustic/noise reduction.

Snug as a bug in a rug.:)

Guinness69

I got Biofoam insulation done and am amazed with the result

Well here again . I had my attic done the day before yesterday. I'm not joking but the difference in the house is amazing. The heating is switching off much quicker in fact it never turned off before getting this done. It ran for the full time it was set for say 4 hours in the morning. The house was warm but due to the heating running. Once it turned off the house would be cold in no time again. I looked into a good few companies and there is an element of the tarmac type operator out there. I think the equipment that they use is most important to get the mix right. If your getting this job done look into the firm doing the job. I got this done for way less than the top quote but what made me decide on the co that did it was the equipment they had. The expertise really only came to the fore after they had done the job.
My job was not an easy one as I live in a dormer there was a lot of crawl space. The guy doing the job broke a water pipe. They were old hard plastic type pipes any kind of touch off them and they would crack. Well not joking they replaced the pipe to two sinks all the way back to the tank for free. There was no water damage as they reacted fast.

This morning I went out to the car in my shirt to find it was freezing out had to go back in to get water for the window on the car I can tell you I grabbed my coat too. In the old days like the day before I would have had my coat for sure

Guinness69

Another thing which was a bonus we never thought of was. We live on a flight path and the noise reduction is big.

paddy147

Guinness69 wrote: »

Another thing which was a bonus we never thought of was. We live on a flight path and the noise reduction is big.

thats one thing i noticed aswell,big reduction in noise pollution.:)

laugh

Ok, so some other diy jobs got priority ahead of this last year and I'm back looking at it.

My rafters are only 110mm deep, how will I achieve the recommended u-value to have a living space upstairs?

Use a 40mm baton and 70mm kingspan and then insulated plasterboard over that?

Do I need any membrane between these?

BryanF

laugh wrote: »

Do I need any membrane between these?

yes and retain ventilation between felt and insulation

laugh

BryanF wrote: »

yes and retain ventilation between felt and insulation

I intend, to leave a gap the width of the baton between the felt and the rear of the installation.