Fire regulations for loft conversion

[newgirl]

Hi,
I am in the process of buying a 2 bed terrace. The loft also has been used as a 3rd bedroom by the current owner but the house is not being sold as a three bedroom house. The loft is carpeted and has a velux window in, but is accessed by a wooden loft ladder.
I understand that for the room to classed as "habitable" the floor has to be able to withstand fire for 30 mins, there must be alternative stairs or exit to the outside etc, but I am unable to find any info about what is necessary for party walls - my homebuyers survey came back the other day citing this as a fire and security risk as there is no fire break; but there was no indication whether this was a legal requirement as the space is not technically a "room".
If anyone could give me any information about this it would be very helpful!

 

[masona]

I am in the process of buying a 2 bed terrace. The loft also has been used as a 3rd bedroom by the current owner but the house is not being sold as a three bedroom house.

That's because no planning or building permission was applied

If anyone could give me any information about this it would be very helpful!

You can get free advice of you pop down to your BCO. Difference area have slightly difference rules so best to get the correct advice for your area.

 

[felix]

I strongly suspect that your 'room' is a just a boarded out loft. You can learn a lot by measuring its floor thickness. Anything less than fifteen inches suggests that there is no new floor up there. As a non-habitable room, very few regulations apply. Anybody can cover their joists with chipboard and the walls with plasterboard to make storage space. If there's no insulation in those walls it'll be freezing cold in winter. What I'd be most worried about however is that whoever boarded it out might have removed roof supports to get a clear space. Did you get a structural survey?

 

[DAZB]

What are you basing the 15" measurement on Felix ?

12.5mm plasterboard - 8 X 2 joists - 22mm chipboard floor - ....seems to be the norm in general .

 

[felix]

That would be normal if the loft was built with a loadbearing floor from the outset. It's more usual to find 4" joists strung between a few deeper beams holding up a ceiling. When you try to put a new floor above this, the best you are likely to achieve is to have your new floor joists running at right angles above the existing 4" ones and with a variable gap because the old ceiling isn't level. They will be slung between steel beams at the edges of the new room and, because of the wide span, they are likely to be 9" joists. Add the plasterboard below and the flooring above and you've got something close to 15". One alternative is to demolish the original ceiling and rebuild it as a floor but think of the mess in the rooms below!

If you see a loft floor only 9" thick it's a pretty fair bet that somebody has used the existing roof beams, perhaps with new ,deeper joists alongside the old ones - or maybe they just added extra wood on top of the old ones. Either way round this is not a proper floor for a habitable room.

Having said all that, I find it odd that you can slap a layer of chipboard over those 4" joists then pile it to the rafters with heavy boxes and nobody from the council bats an eyelid!

 

[chappers]

Rubbish I spend nearly every day doing loft conversions and in 6 years of running my own company I have only twice come accross a set up where the new floor joists are at right angles to the existing ceiling ties.
what happens usually is that beams are fixed at right angles to the ceiling ties and the new floor joists hung from these, usually 8 by 2or3 and occasionally 9" these are hung down from the beams 25mm above the existing ceiling plaster board so at most 12.5mm plasterboard 25mm gap 225mm joists and 22mm chip board so at most 11.5 inches and most likely10.5".
Using larger joists alongside/inbetween the existing ceiling ties is normal practice.

 

[chappers]

In response to the original question then, for a habitable room you need 1/2 hour fire protection all round basically that includes your ceilings and any party walls or external walls within 1m of your neighbours and any ceilings along the main escape route down to the front door., an alternative to the stairs is needed as a means of escape (usually a MOE velux to the front elevation).Mains powered, interlinked smoke alarms to the room and all landings along the means of escape route are required and also a self closing fire door to the loft room and at least self closers to all habitable rooms or kitchens that open onto the escape route.
Bear in mind these are the current requirements and your loft will not be breaking any rules if it was constructed with building consent at a time when the regs where different.
If this room was not constructed as a habitable room then these regs don't necessarily apply but remember if you are likely to be using the room as a habitable room the only person you are putting in danger is yourself or your family, alot of the rules may seem petty but they have been built up over a long period of time with safety in mind.

 

[DAZB]

I have just done a loft conversion on a mid terraced town house I have bought to develop and sell and I removed all the upstairs ceilings and ceiling joists and replaced with 7 X 3 joists ( an approved alternative to 8 X 2 's ) and then laid 22mm chipboard for the floor. The joists run from front to back and sit on and overlap each other on the stairwell walls internally . A layer of 12.5mm board on the new ceilings and skimmed with Board Finish. Building Inspector is happy and so am I thinking of the new resale value ! Looks like me and Chappers could teach you a thing or two Felix.

 

[felix]

I must bow to Chappers' superior experience who does after all have his/her own loft conversion company. I only crawl around them putting pipes and wires in. All the ones I've been in were built in much the same way with their joists parallel to the roof ridge, hence my assumption that this was normal. Bad idea.

I've also been in a cowboy loft conversion where the 'floor' dips noticably at two points. Another bad idea?

DAZB, there's nothing wrong with demolishing your ceilings and building a new floor from scratch. That's the best way to do it if you don't mind the mess - and those 8x3 joists are roughly 20% stronger than 9x2's.

Newgirl, the rest of my original advice still stands. Just because a 'floor' has carpet on it that doesn't mean the room is up to habitable standards. If I was buying that house, it wouldn't be the lack of insulation or a fire escape that would worry me - you can always add those - but the possibility that somebody has severely weakened the roof. In the worst case scenario your walls could burst out sideways. It's worth checking this out before you part with your money - and I think Chappers would agree with that.

 

[chappers]

would agree with that its always a hard one if it was done with building regs your solicitor should be able to find out by doing a search with building control, if it wasn't its hard to tell whats been done, but as you say sagging roofs and floors are usually a give away, this not advertising it as a habitable room is always a dodgy one and suggests its not been done to regs so caveat emptor.

 

[masona]

8x3 joists are roughly 20% stronger than 9x2's.

No less than 9"x3" in my area, even have to nuts/bolts 3 together with dog connectors for around stairwell trimmer, one of them was 6m in length