How big does a garden need to be for fire safety?!

[frogs4all]

We're renovating a 2-bed 1905 brick terrace house in London. Formerly a shop but used as a residence for 20+ years and had change of use.

 

We're not changing the layout of internal rooms or windows but Building Control has raised concerns about fire escape from the 1st floor back bedroom window: "Ground floor is an open plan layout so means of escape from the rear bedroom is a problem because of the length of the garden." The garden is really a small, tiled yard about 1.4m wide and 5.5m long with brick walls separating it from 2 neighbours' gardens. No concerns about the front bedroom windows which open above the street. I am struggling to understand why the open plan ground floor and the size of the yard is relevant here. Proximity to the house perhaps? Evacuees could always go over the wall to a neighbouring garden and I'm happy to provide a way to assist with that if necessary. My intuition is that getting out of a 1st floor window and down 3m+ to ground level would be a more difficult feat than getting over the wall.

 

I've not seen any regulations concerning the size of the outdoor space so any guidance or thoughts would be very welcome! Thanks in advance!

[Mr Punter]

To be a fire refuge I think it needs to be deeper than the building is high.  If it is existing and no changes to the house I don't know why BC are interested?

[Conor]

Its because there is no escape route for the first floor, as the ground floor is a single room, it effectively means all the rooms on the first floor are a room within a room. You'll need to create a separate escape route (e.g. separating the stairs from the open area downstairs), other fire mitigation system (sprinklers) or as BC has said a refuge area, which you cant provide.

[frogs4all]

Interesting, thanks very much Mr Punter. The housing is densely packed so there's no way we or any of our neighbours would pass the fire refuge requirement.

 

We are moving the partition wall between the 2 bedrooms slightly to even up the room sizes. This results in the back bedroom being about 450mm longer. There will be slightly less space in all rooms due to internal wall insulation and there will be new windows which will allow for egress in a fire. I don't think any of those should have an impact on their assessment but happy to be corrected.

[frogs4all]

3 minutes ago, Conor said:

Its because there is no escape route for the first floor, as the ground floor is a single room, it effectively means all the rooms on the first floor are a room within a room. You'll need to create a separate escape route (e.g. separating the stairs from the open area downstairs), other fire mitigation system (sprinklers) or as BC has said a refuge area, which you cant provide.

 

Thanks Conor.

 

I am not sure I understand the "room within a room" idea but I think I understand what you mean: there is no way to contain a fire on the ground floor (e.g. by closing a door) to create a protected escape route through the ground floor? Have I understood that correctly?

 

If so, I'm not sure why concerns have not been raised about the front bedroom.

 

Because of the old shop layout, the stairs start at the back of the living area, right next to the kitchen. We could provide a door to the living area and a door to the kitchen at the bottom of the stairs if that would help. Either door could be closed to create an escape route through the living room to the front door or through the kitchen to the back door.

[Mr Punter]

If you have not made any changes other than even up 2 rooms, you don't need Building Regs.  If you have, for example, removed a corridor or moved the kitchen it could be required.

[frogs4all]

8 minutes ago, Mr Punter said:

If you have not made any changes other than even up 2 rooms, you don't need Building Regs.  If you have, for example, removed a corridor or moved the kitchen it could be required.

 

Nothing like that. We've involved Building Control because we've replaced the original, bowed timber beam which supported the first floor with an RSJ and have had to replace the ground floor joists. We also intend to insulate to current standards or as close as we can get. So there's a lot of change to the fabric but not to the layout.

[Mr Punter]

The only approval you need is for the replacement beam, floor joists and insulation (fabric improvement).  They may not like the current layout, but tough.

[AliG]

I found an interesting discussion re this here -

 

https://www.cross-safety.org/uk/safety-information/cross-safety-report/no-worse-existing-1148

 

The argument seems to be that too many alterations get away with saying they are no worse than the previous building and that this has been too loosely applied in the past. Maybe this is what BC are considering.

 

Nevertheless in your case I think the alterations are minor and they new windows provide a means of escape which is an improvement.

 

 

[kandgmitchell]

The relevant bit about depth of gardens etc is on page 15 of the Approved Document to Part B Voilume 1, in particular diagram 2.5. I can't get it to copy so as to post here.

 

However, Regulation 4 (i.e the law, not the advice in an AD) says in paragraph 3):

 

(3) Building work shall be carried out so that, after it has been completed—

(a)any building which is extended or to which a material alteration is made; or

(b)any building in, or in connection with, which a controlled service or fitting is provided, extended or materially altered; or

(c)any controlled service or fitting,

complies with the applicable requirements of Schedule 1 or, where it did not comply with any such requirement, is no more unsatisfactory in relation to that requirement than before the work was carried out.

 

The significant bit is "no more unsatisfactory in relation to that requirement than before the work was carried out."

So the impact of moving the partition between the two bedrooms, on the original means of escape has to be considered assuming all other parameters haven't changed. I can't see how moving the partition can be said to be making the existing situation more unsatisfactory. Indeed if your new windows are better for escaping through then arguably this is more than adequate compensation.

 

Myself, I'd acknowledge BC's concerns (and they are fair to raise) but politely point out you are not making the situation any worse and hence Regulation 4(3) applies. 

[frogs4all]

Thanks for all your excellent advice, everyone. Much appreciated.