Converted loft - requires insulation - please help!

moob_2

27col wrote: »

If you are proposing to get the pitched roof area insulated you are wasting your time and money, unless you are going to be living up there. If you are, then the floor would need to be strengthened.. All you are doing is a adding huge volume to the existing volume of your house. Any heat retained by the insulation will be in the roof, above your habitable rooms. The only practical way to insulate the house is is to lift the boarding and to add the insulation where it can do the most good. Once you have a few boards up the rest will probably come up without too much trouble.

As I mentioned in my OP, the loft space is t&g - it is also converted into a bedroom - the house essentially has a ground, 1st and 2nd floor. We intend to use the 2nd floor (loft area) when the family grows, so there's no point insulating the floor of it.

seven1969

Ours is also in use as a bedroom. We live in a bungalow so there is only 1 floor plus the loft conversion.

Moob - I had a look at the Space Blanket site and in the FAQ it states that you can't push Space Blanket up into the eaves. Wait until I tell my OH. Tee hee! Not that he'll listen - if he wants to use Space Blanket, then that's what we'll be using. Apparently, we should use Rafter Roll. Which I'm trying to source just now. I really should be working but never mind........

littlesos

We are also currently going through this. We have a dormer bungalow, with hardly any insulation. DH also thought about sliding insulation up behind the plasterboard, but this wouldn't work. This is what we have done......

Pulled down all the walls and ceilings from the upstairs/loft conversion part of the bungalow and we are fitting kingspan/celotex between and under the rafters. As this is a 1930's bungalow with a purlin construction roof we have very shallow rafters (75mm) so with a 50mm air gap that only left us with room for 25mm insulation between the rafters, hence the need to insulate under as well. We looked at loads of different methods but this way seems to give us the best insulation for the most reasonable cost.

If we had more money I would have had the bungalow re-roofed with a breathable membrane so that we could insulate without the 50mm airgap, and increase the space inside the rooms.

We looked at the foil layered insulation as this seemed to offer a perfect solution, however on investigation it seemed that it may not perform as well as was claimed, and there was also reports of it rustling. It was also horribly expensive, so on balance we decided to sacrifice some space to save some pounds.

Rach

Myrtle

We used Kingspan expanded foam, foil-backed insulation in our loft space. It was cut to exactly the right size to fit between each rafter then visqueen(sp?) (thick plastic) was put on top (hammered into the rafters to hold in place). It was then plaster-boarded over the top. As long as you've got slate tiles or ventilation on the otherside this should be ok. We had our slates replaced recently and there was no sign or any problems after 15 years.

Another alternative is to use plasterboard with insulation pre-attached which you just screw directly over the existing plasterwork - make sure the screws go into the woodwork though!

There are lots of people who can give you advice on how to do it yourself. We talked to these people http://www.syec.co.uk/ and got all the insulation from here http://www.sheffins.co.uk/

Usual "I'm just an ordinary idiot member of the public" disclaimer applies....

moob_2

seven1969 wrote: »

Ours is also in use as a bedroom. We live in a bungalow so there is only 1 floor plus the loft conversion.

Moob - I had a look at the Space Blanket site and in the FAQ it states that you can't push Space Blanket up into the eaves. Wait until I tell my OH. Tee hee! Not that he'll listen - if he wants to use Space Blanket, then that's what we'll be using. Apparently, we should use Rafter Roll. Which I'm trying to source just now. I really should be working but never mind........

Cheers, I read that, this is what it says:

No, you should not push loft insulation into the eaves as it prevents air from flowing and removing moisture. Use a proprietary crossflow ventilator or ensure a minimum 25mm air gap.

Now, what I get from this is that they assume you may have other insulation in place - such as on the floor of a loft conversion. I would therefore assume you can install it as long as there's an air gap etc - which isn't a problem as the depth of my eaves is 120mm - even though the Space Blanket says 200mm, it's only like 50mm thick in reality. That would therefore leave plenty of air gap. I'm proposing to keep it in place by using some chicken wire, which would not cause ventilation issues.

I will contact the manufacturers to confirm my assumptions and get back.

Thanks to everyone who has contributed on this thread.

moob_2

Just contacted the manufacturer - there's no problem installing space blanket into the rafters at all - it's merely not recommended as it won't stay in place - they have another product called Rafter Roll, which is recommended for this use.

It's important to identify what the rafter, eaves etc are...

The eaves are the space between the rafter (slop of the roof leading to the top) and the floor of the loft:

seven1969

Oh my word moob. Technical drawings - this is way beyond me. However, OH is a roofer to trade therefore, I will bow to his knowledge for once! It's definitely one for the boys! Why am I even getting involved I wonder?

Thanks for all your advice - it certainly helps to just pick up the phone and speak to the experts.........