Is insulation worth doing?

ecolozical

Hi all,

I was wondering if I could prevail on anyone knowledgeable on the subject of partial insulation to advise me...

I bought my house in Jan 2013, and thus I have more or less spent 2 winters in it. It has a loft conversation with sadly no insulation, so the attic level is mind bendingly roasting hot in the summer, and hideously expensive to keep liveable in the winter... and last winter wasn't even the coldest... My gas bill in the summer is about £10/month, and up to about £160/month in the winter.

Because it's a loft conversion, access is awkward, and any insulating I can economically do is clearly going to be a little suboptimal, but... where the room height gets down to about 140cm built in storage has been put in, and roof under boarding added.

I can clearly remove all the under boarding and shove some pretty decent insulation in there no problem and do a reasonable job of it because it is accessible.. and I imagine this will make some difference. Question is, will it be worth it? This would cover perhaps 35-45% of the roof area, but it will be the lower parts, where less heat is lost from...

Another, rather dubious plan, and I've not quite decided if this is possible yet, is to ram long strips of insulation board up between the rafters from the built in cupboards, feeding it towards the roof ridge... This clearly has MANY difficulties, such as getting the cut right so it sticks without so much friction that it can't be shoved, and obviously the gap between the rafters may vary fractionally to confound me, and will I be able to get it up there without it getting out of position (leaving an air gap to the felt, etc)... and if I achieve all this, will it potentially count for nothing because I will never achieve a really good coverage (there's realistically bound to be some small, or embarrassingly large gaps at the ridge at least) and I'm imagining a nice draft getting in and around and whisking all my heat away between the insulation gaps, etc...

Any comments would be most welcome!

Furts

Trying to push insulation boards up between rafters is a non starter. The other plan is possible. Insulation is more complex than many appreciate. It has to considered in conjunction with air tightness and ventilation. The aim is also to avoid condensation and rot. Meticulous attention to detail is required.

Anything you do will improve the situation, but only if it is done with care. The end result will still be a hot room in summer and a cool room in winter. This is the reality of living in a loft.

Celotex and similar sheets are expensive, especially when considering 100mm or more which is what is required in a roof. Then there are the vapour barrier and breather membrane so it becomes a task to do the work.

lstar337

If insulation has not been done and access is awkward, are you sure the room is designed to be lived in?

It could just be intended for storage.

Mankysteve

If not been insulated I would be questioning if the rest of the conversion has been done done to required standards.

If you don't mind loosing some roof height you could also put in some insulated plasterboard sheets up all the way around.

JP08

I sympathise with your plight. We have a '60s built semi chalet style house - ie the top 4 feet of the upstairs floor is roof shaped. Insulation is being upgraded on a room by room and roof by roof basis.

When the flat roofs on the dormers were redone, all we could get in was 10cm of celotex between the rafters. When the bathroom was gutted, the insulation in the sloping ceiling was upgraded. But at present the sides of the dormers in the two main bedrooms and the insulation in the sloping ceilings (between ceiling and outside roof structure) is whatever was shoved there in ~1963 - probably next to sod all. Short of pulling down the ceilings / replacement of the tiled roof I can see no way of upgrading this insulation. Neither is cost effective compared to the saving on heating bills.

ecolozical

Thanks Furts, your discouraging reply unfortunately makes a lot of sense. Further research following your reply leads me inescapably to conclude, as to be fair I originally suspected, that pushing between the rafters is a daft plan.

Re: 100mm or more needed, there wouldn't be space for that with adequate ventilation, but even 30mm must surely be an improvement, if installed correctly and effectively... It's a reduction in heat loss still after all...

I will, then, with care, attend to those parts where access is sensible and installation can be done well, to try and limit the area where heat can be transmitted away.

lstar337, you are quite correct in essence, though it depends on what criteria you use to determine if it is "designed to be lived in". If you take modern building standards, then by definition, given the lack of insulation, no, it's not, and apart from insulation issues, the stair well width and stair tread characteristics would also fail fire regs. However, this is what I think estate agents refer to as an 'original conversion' done a very very very long time ago (not sure exactly when) so it would have met the (non existent) building regulations at the time (!) In terms of its presentation, it has been refurbished and equipped to a high standard, with various fitted furniture, cupboards and 2 radiators, and really whilst it could not be defined as living space by modern building regulations, and whilst I certainly wouldn't choose to use the room as a living or bedroom space as such, it is perfectly usable as such, if one pays to heat it! For my part, I essentially use it as a study/office, since it doesn't seem sensible to use it for anything else. I have a desk there and I go and use my computer up there, in my boxer shorts in the summer, and 3 fleeces in the winter! :rotfl:

Also, it's not just about this room really, I focused a bit much on the room really when it's not really the point. At the end of the day, heat rises, and as long as there's no insulation at the top of the house, if I use that top room or not, the heating bill is still going to be harsh.

Mankysteve, as you will assess from the above, the cost and effort of retro under fitting insulation, would be uneconomical, and the loss of the amount of ceiling height in order to do a good job of it would be quite inconvenient, it's ok at the moment, but not by a great margin.

JP08, it does sound like we're basically in the same boat, the cost of dealing with these issues for their own sake doesn't make sense, paying the gas bill for years until the roof needs replacing (or whatever) is realistically going to be the cheaper lesser of 2 evils.

Ectophile

If 100mm isn't possible, you can get some clever foil insulation these days - it's like a stack of space blankets. Not cheap, but a lot thinner than the conventional insulation.

ecolozical

I saw something like this the other day, and bookmarked it so I could come back and research it properly when I had time:

insulation-actis.com

Furts

ecolozical wrote: »

I saw something like this the other day, and bookmarked it so I could come back and research it properly when I had time:

insulation-actis.com

Be very wary of this product - it was banned for many years. The installation must follow the manufacturers strict guidelines or it will not work.

The rules on roof conversions have existed for generations so I suspect that your loft was bodged and the estate agent has lied, or misled, to cover up this issue.