Garden Outbuilding - building regs?

[Apacheuk]

I'm considering building a garden room / outbuilding down the bottom of the garden. I'm no builder but I'm toying with the idea of using a SIPs garden room kit as an insulated brick one is expensive.

I've seen 6m x 3m design from supersips that we like, it's going to be located within 1m of the garden boundary on two sides. Building regs say:

If the floor area of the building is between 15 square metres and 30 square metres, you will not normally be required to apply for building regulations approval providing that the building contains NO sleeping accommodation and is either at least one metre from any boundary or it is constructed substantially of non-combustible materials.

As its 18 square metres, it needs to be constructed substantially of non-combustible materials so instead of cladding it in wood, we're thinking of using brick slips as we like the look of it.

So would this be acceptable?

or does it not matter as when looking at other peoples pictures theirs are covered in wood and right next to the garden boundary.

 

[Nakajo]

The floor area isn't 18m2 (although it may still be a fraction above 15m2)

 

[frutbunn]

There is no definition of "substantially non combustible" in schedule 2, however simply cladding the side in brick slips would not, in my opinion, make it exempt. This is also the policy of all the LA's I have worked at or with.
Simple solution would be to position it 1m from the boundary. If this is not possible you can make it comply by making both sides of the wall on this boundary 30 minutes fire resistant, the brick slips will satisfy the requirement for surface spread of flame. Please not there may still be further requirements on other elevations relating to fire separation but this depends on the surface area and proximity to boundary. The boundary, for the purposes of B Reg requirements relating to fire separation, may be taken as a "relevant" boundary to the centre of a footpath, road etc but not for assessing B Reg exemption, this relates to the boundary of the property.
Floor area is measured internally for B regs.

 

[Apacheuk]

Thanks for the reply

you can make it comply by making both sides of the wall on this boundary 30 minutes fire resistant, the brick slips will satisfy the requirement for surface spread of flame

So if I battened on fire rated cladding boards to the sips walls and then do the brick slips. This should meet the requirements?

The boundary, for the purposes of B Reg requirements relating to fire separation, may be taken as a "relevant" boundary to the centre of a footpath, road etc but not for assessing B Reg exemption, this relates to the boundary of the property.

The garden is surrounded by the neighbours gardens on three sides and the road at the front of the house is at least 25m away.

Floor area is measured internally for B regs.

Thanks, need to find out what it is from them.

So I assume if it works out less then 15m2 it negates the need to meet building regs?

 

[Apacheuk]

The floor area isn't 18m2 (although it may still be a fraction above 15m2)

Seems obvious now you pointed that out

 

[frutbunn]

So if I battened on fire rated cladding boards to the sips walls and then do the brick slips. This should meet the requirements?

As long as it is 30 minute fire resistant, but must be on both sides of the SIPS panel

So I assume if it works out less then 15m2 it negates the need to meet building regs?

If its under 15sq m then it is exempt from B Regs regardless of position of boundary or whatever material it is built with.

 

[Apacheuk]

Thanks. Just trying to get my head round all this stuff

 

[Antscran]

As long as it is 30 minute fire resistant, but must be on both sides of the SIPS panel

I was looking at SIPS options as well, so if you covered the outside in suitable cladding and plaster boarded the interior would that be ok?

 

[frutbunn]

I was looking at SIPS options as well, so if you covered the outside in suitable cladding and plaster boarded the interior would that be ok?

No, in the OP's situation you need to have fire resistance to both sides, as well as gthe inner face there would have to be suitable fire resistant board fixed to the external face prior to the brick slips. The brick slips would only give the required surface spread of flame, I have assumed the brick slips will not contribute any fire resistance, but I've not checked any technical information on brick slip cladding.

 

[Apacheuk]

I contacted the company and the dimensions are 6.1m x 3.05m externally and the internal floor area is 5.9 x 2.85 = 16.8m². Therefore would need to comply with building regs.

3 sides will be more than 1mtr from any fence/boundary so shouldn't be an issue with fire ratings.

That leaves one side that will be near the garden fence. So if I clad this one side with metal corrugated roofing sheets that should work?

 

[frutbunn]

There may still be a requirement relating to fire separation depending on the dimensions of the elevations and distance to boundaries or the centreline of any footpath/road etc
The side that is within 1m requires fire resistance to both sides, the steel cladding will give the required surface spread of flame, however will not contribute any fire resistance.