What insulation can i use in my rafters

Kevcunny67

Hi there im converting my loft space and just wondering what to use for insulating my rafters. Celotex kingspan etc is a bit outside my budget. So was thinking of rockwool next however there is a loft roll in travis perkins just now for 12£ a roll but says is primarily used for pitched roofs at ceiling level. Would this comply will building standards and stuff if i was to put this in my rafters as would realy benefit me or is rockwool slabs the best bet. Any help would be greatfull thanks.

Owain_Moneysaver

What method are you using to calculate the U value of insulation required to meet Building Regs and what have insulation system have you put on your Building Regs application to meet this requirement?

You can get manufacturers' seconds insulation boards

Kevcunny67

Not got a method. Just wondering what the standard would need to be.

Kevcunny67

My rafters are 140 was thinking of puttin 100mm rockwool slabs in them. Was on that website earlier today there prices for kingspan etc are not far of some brand new prices.

System

You'll really struggle to get compliance with rockwool (or any other)rolled/batt insulation - check out the maximum permissible uvalues and see what the most cost effective way to do it is, even with 100mm rigid insulation you are unlikely to comply...

Kevcunny67

I think i can only put 90mm of rigid insulation in so i have 50mm gap behind it for airflow.

System

You then need to add insulation on the inside of the rafter line to get the required insulation values for building regs compliance, it won't comply with soley 90mm of anything ime

Kevcunny67

Ok no problem if i dont do this what will happen ?

Kevcunny67

If i dont comply with building regs and only put something smaller into rafters. I havnt any planning permision either im pretty sure i dont need it.

Owain_Moneysaver

You may not need planning permission for a loft conversion but you will need Building Regulations consent.

If you don't have Building Regulations consent then
- you have no assurance that the work done has been safe
- the work may in fact be dangerous to the point where your house collapses
- the council can take enforcement action requiring the work to be brought up to standard at your expense and they can put a charge on the house (like a mortgage) to reclaim their money
- any prospective buyer will demand to see a Building Regs certificate for the work and without it your house may be unsellable or unmortgageable

You have to comply with all building regs, you cannot just opt out of the insulation requirements, so if you cannot apply suitable levels of insulation to the loft conversion you may have to apply compensating measures to the rest of the house. This will all be detailed as part of your Building Regs application and will be checked by the council building control officer.

Davesnave

Kevcunny67 wrote: »

If i dont comply with building regs and only put something smaller into rafters. I havnt any planning permision either im pretty sure i dont need it.

In the real world, you don't have to comply with anything, because the council probably won't know the 'conversion' is there. You can create a a room on the loft which is poorly insulated, doesn't meet fire regs etc etc and that's exactly what many people do. Some even let their kids sleep in them.

But in the real world, when your house goes on the market, the non-compliant room in the loft won't count as a bedroom and it will be difficult for any future owner to gain compliance. As it's square footage of bedroom space which counts, it won't add any value.

People will just say "Nice storage," but they won't want to pay for it. At best, it's a 'hobbies room.'

And if they're like me, they'll also think, "Aye, aye, Bill the Bodger's been at work here; what else has he done badly?"

A non-compliant conversion is a red flag and possibly a waste of money in the longer term.Go down the non-compliance route on that basis.