Fire regs and attached garages

sydthebeat

I have always being specifying 215 solid block walls between garages and dwellings. This is a throw back from college i think.

But on review it seems that a 100 block wall plastered on both sides will give over 3 hrs fire resistance in accordance with BS 5628 Part3 1985.

So if 100 gives 3 hrs and only 1/2 hr resistance is required, why, more often than not is 215 built?

I have checked the sound regs and these state that:
Airborne sound E1 (1) A wall which
(a) separates a dwelling from another dwelling or from another building, or
(b) separates a habitable room within a dwelling from another part of the same building which is not used exclusively with the dwelling, shall have reasonable resistance to airborne sound

A wall as bolded above would need to be 215 plastered, but can it be argued that an integral or attached garage shall be 'used exclusively with the dwelling'...???

has anyone any viewpoints on this?

RKQ

I don't think sound is a problem as the garage is attached. No nuisance factor associated with your own noise!

Fire regs with regard to ceiling insulation and fire rating would be very important.
As would ensuring that the floor slab is 100mm below the floor slab in the rest of the house - oil / paint spills etc - possible fire hazzard.

I guess the old detail of an attached "Boiler house" always showed 215mm block wall. Maybe this detail, pre-building regulation, is just good practice - good for sound, fire and structural reasons.

Poor Uncle Tom

I think it's a structural throwback. for fire reg purposes a garage built onto a house had the dividing wall taken to the underside of the roof in a gable fashion. This would not be possible to do (very very unstable without intermediate support) in a 100mm (4") wall. I think this is where it came from.

sydthebeat

this arose in a case where the client wanted as much space in the garage as possible. the garage is single storey and the dwelling is dormer. It was decided to bring the external leaf up on an RSJ, therefore leaving 100mm between the garage and the adjoining room. We're certifying so we're trying to conclude that this construction is ok. So assuming all the other aspects are covered ie 100mm upstand, insulated RSJ etc, i cant see any reason why this doesnt conform to regs..???

muffler

Poor Uncle Tom wrote: »

I think it's a structural throwback. for fire reg purposes a garage built onto a house had the dividing wall taken to the underside of the roof in a gable fashion. This would not be possible to do (very very unstable without intermediate support) in a 100mm (4") wall. I think this is where it came from.

You beat me to it. Thats what I would have thought also.

sinnerboy

1. risk of vehicle impact damage
2. wall is an element next to an unheated space and will require insulation

would concern me

sydthebeat

sinnerboy wrote: »

1. risk of vehicle impact damage
2. wall is an element next to an unheated space and will require insulation

would concern me

very good point.
part L 2002 and 2006 both require an upgrade here.

so even 215 walls would require insulation in these locations.

re the impact damage, there are 4 block piers over a length of approx 7 metres so im not so much worried about this one.

sinnerboy

often a difficult upgrade . 215 solid wall between house and garage - with stairway within the house - no space for dry lining .

Mabye AAC blocks would help with your situation Syd . The u value can be adjusted ( improved ) because of semi shelter of garage

sydthebeat

sinnerboy wrote: »

often a difficult upgrade . 215 solid wall between house and garage - with stairway within the house - no space for dry lining .

Mabye AAC blocks would help with your situation Syd . The u value can be adjusted ( improved ) because of semi shelter of garage

i have looked at compliance with current part L 2002 as they are the applicable regs, and i think a u value of approx 1.0 is required. This can be easily done by composite plasterboard on the exposed wall in the garage.

either that or a fixed integrated radiator....

sinnerboy

sydthebeat wrote: »

either that or a fixed integrated radiator....

must be zoned alone - or you must count in area of and elements to the garage in DEAP calcs

sydthebeat

sinnerboy wrote: »

must be zoned alone - or you must count in area of and elements to the garage in DEAP calcs

DEAP isnt applicable as its old regs.... dwelling substantially complete by April 2008....

I think the best option is to dryline with CPB..... least hassle.

sinnerboy

sydthebeat wrote: »

DEAP isnt applicable as its old regs.... dwelling substantially complete by April 2008....

Could skew the BER cert rating though when that time comes

sinnerboy

sydthebeat wrote: »

DEAP isnt applicable as its old regs.... dwelling substantially complete by April 2008....

Could skew the BER cert rating though when that time comes .

CPB - i agree

sorry for the sort of double post - PC was experiencing hiccups ..... ( not me ! )


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