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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Carpentry Questions >> Loft conversions https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1089668860 Message started by mailee on Jul 12^th, 2004, 10:47pm

Title: Loft conversions
Post by mailee on Jul 12^th, 2004, 10:47pm

Can any of you guys tell me what is involved with loft conversions?. I know you need planning permission and possibly buidling regs, but just exactly what is involved with the woodwork side of it, Roof trusses, stairs, joists etc. and how about the windows in the roof?. Would appresiate any info you can give. Is it a DIY project or do you have to have a reputable joiner/builder to do the work?. ???

Title: Re: Loft conversions
Post by HandyMac on Jul 12^th, 2004, 11:00pm

I have no experience so the following is just what I understand.

You'll need to get building regs approval, that will probably involve an architect drawing up plans. You may well need to get a building company involved 'cos these loft conversions aren't generally DIYable.

There are a couple of issues that come to mind:

1) trusses in the loft are probably not going to be strong enough to support a proper floor, and may need strengthening. This may involve putting some extra support brackets on the side walls to take the extra truss thickness.

2) If this is to be habitable space you get into a whole new ballgame about providing a staircase which provides an adequate escape route in the event of fire. You can't make do with a simple loft ladder.

Andrew

Title: Re: Loft conversions
Post by Robbo on Jul 12^th, 2004, 11:21pm

There are a number of criterea that need to be met in relation to a loft conversion the foremost one as far as building control are concerned is the fire regs. You will need to provide half hour fire protection to ceilings by overboarding (first floor) or fire retardent insulation between joists hung on chicken wire, (though might not get away with that theese days) you will need an enclosed fire checked stairwell with fire doors possibly self closers on doors below attic.
There must be an accessable top hung roof light at low level for means of escape.
Floor joist will need upgrading and need to bear on internal walls, you can not glue and screw to existing but straddle the existing joist with probably 7 or 8x2.
triple R or Kingspan insulation between rafters leaving a two inch air gap between underside of roof covering and insulation, under no circumstances use rockwool type insulation.
You will probably need an engineers report for the plan submitted in regards to the proposed joist layout, all in all there are alot of rules to abide by.... however if you are turning the attic into what you might term a hobbies room, sewing room, utillity room etc etc then you do not need planning peremission as long as it wiil not be a habbitable space, therefor you can convert as you see fit and what you do with it is your business �;) ;) ;) ;) ;) ;)

Title: Re: Loft conversions
Post by greg on Jul 13^th, 2004, 7:47am

just to add that most of the loft conversions ive had any involvenment in have required steels to hang the joists on due to the span

Title: Re: Loft conversions
Post by splinter on Jul 13^th, 2004, 7:15pm

malee,
� � � � �i noticed you mentioned �roof trusses .Modern trusses �rely on the way they are made for their strength.They can not be cut to provide space in a attic
I �rescently read a newspaper article about a man ,who done this �in �a housing assocation house �that he was living in.
Apparently �he is was not very happy with the �30,000 they estimated �it would cost repair his handy work

Title: Re: Loft conversions
Post by greg on Jul 14^th, 2004, 7:01am

iwas under the impression that modern roof trusses can be done - but involves a fair bit of work what with having to put in dwarf stud walls and collar ties etc etc - ive seen it done a couple of times and building inspector had no problems with it

Title: Re: Loft conversions
Post by splinter on Jul 14^th, 2004, 6:48pm

greg,
I do understand that all things are possible :).Unfortunetly they are not always viable.The cost would be very high. :o

Title: Re: Loft conversions
Post by greg on Jul 14^th, 2004, 7:30pm

yeah good point splinter - you can have it but at a price - guess it depends on how bad you want / need it

Title: Re: Loft conversions
Post by Robbo on Jul 14^th, 2004, 11:01pm

Surprising as it may sound it is invariably cheaper to take a trussed roof off in full and cut in a traditional roof, then reinstate tiles rather than attempting to convert from the inside. On a traditional cut roof there is no stress on the original rafter so even 4x2 need no alterations other than additional 2x1 or 2x2 tacked to the underside so as to gain the depth for in between rafter insulation. In short a trussed roof is a financial no no. steels are often a requirement on longer spans hence an engineers spec though often enough you can get by with timber trimmers or double trimmers on shorter runs.

Title: Re: Loft conversions
Post by splitthumb on Jul 17^th, 2004, 10:14pm

Just finished one. Extended Dormer,New 230mm floor joists between existing,any joins must rest on supporting walls,
Insulation to Part E between floor Joists-150mm Fibreglass,
Sloping ceilings Kingspan-50mm between50mm overboarded underneath.
Horizontal Ceiling 110mm between if you have 50mm airspace,or create warm roof,with insulation on top of decking.
Dormer cheeks also 110mm. All insulation to part Hell (L)
Have fun.

Title: Re: Loft conversions
Post by Robbo on Jul 17^th, 2004, 11:02pm

Expensive job warm roofs!