Partial conversion of loft - how far to go before regs apply

[jc292]

I'm thinking of "part converting" the loft, which is currently fully boarded for storage with lighting and accessible by ladder.

By "part converting" I mean I'm putting insulation between the rafters and plasterboarding it all up, the plastering and maybe putting in some power. The idea is not to turn it into a "habitable" room, but to use it as a kind of hobby room with a carpet and also a velux window for a telescope or something. I would get into it by the existing loft ladder. I would use the existing floor which is just board over the ceiling joists (no intention to strengthen the structure with RSJ etc. as I won't be putting furniture up there and just a few boxes)

Do you think I need building regulation approval for this - as I'm not putting in a staircase or using it as a bedroom etc? I'm not sure what counts as a "habitable" room in that sense.

My other question is how much insulation should I put in the walls i.e. between the rafters, so that if I did save for a proper loft conversion later I could at least reuse what I'd already done with this part-conversion idea.

I realise this must get asked a lot and info is in the building regs. I have read a lot of regs documents on various local council's pages but to be honest I find them hard to understand and I don't really get how to translate U-values in insulation thickness. I just want to know what thickness of kingspan I should buy to lay against the walls and for the roof/inbetween the rafters (which is a "cold deck" - tiles then felt). The house is a standard 50s build brick house. What would people advise?

Sorry is this is in the wrong area of the forum - my first post so please be kind! Thanks for your advice!

 

[freddiemercurystwin]

The only way you'll get regs approval is by deeming at a habitable room which involves the fitting of a permanent compliant staircase.

No stars, non- habitable.

For the roof you want 110mm kingspan k7 insulation fitted between rafters and continuous layer of 25mm kingspan k7 fitted beneath

For the dwarf walls you want 100mm kingspan k7 insulation between the studs.

Untitled

• freddiemercurystwin
• 25 Apr 2010
• 24

 

[jc292]

Thanks very much for that fantastically clear reply!

 

[freddiemercurystwin]

That'll be £100 please!

 

[DevilDamo]

It may be worth while checking to see if Planning permission is also required. It may fall within your PD rights (if they haven't been removed and you live outside of a conservation area/listed building).

 

[jc292]

Thanks DevilDamo. It is in a conservation area - but I'm assuming apart from perhaps the Velux window everything is internal and I wouldn't need planning permission (its not a listed building or anything like that). Does that sound right or could they be more strict on PP requirement?

Maybe I wouldn't even need permission for the window if its just a flat window (not considering anything structural like a dormer?)

 

[DevilDamo]

As per the Planning Portal...

Planning permission is not normally required. However, permission is required where you extend or alter the roof space and it exceeds specified limits and conditions.

Under new regulations that came into effect from 1 October 2008 a loft conversion for your house is considered to be permitted development, not requiring an application for planning permission, subject to the following limits and conditions:

•A volume allowance of 40 cubic metres additional roof space for terraced houses*
•A volume allowance of 50 cubic metres additional roof space for detached and semi-detached houses*
•No extension beyond the plane of the existing roof slope of the principal elevation that fronts the highway
•No extension to be higher than the highest part of the roof
•Materials to be similar in appearance to the existing house
•No verandas, balconies or raised platforms
•Side-facing windows to be obscure-glazed; any opening to be 1.7m above the floor
•Roof extensions not to be permitted development in designated areas**
•Roof extensions, apart from hip to gable ones, to be set back, as far as practicable, at least 20cm from the eaves

*Bear in mind that any previous roof space additions must be included within the volume allowances listed above. Although you may not have created additional space a previous owner may have done so. Calculate the area and volume of your works using our Volume Calculator

**Designated areas include national parks and the Broads, Areas of Outstanding Natural Beauty, conservation areas and World Heritage Sites.

http://www.planningportal.gov.uk/england/public/buildingwork/projects/workcommonloftconversion/

So you better check with your L.A. to prevent enforcement action being taken and works coming to a stop on site.