2 Storey Split Level House with Loft Conversion - Protected Staircase

[wessex101]

Quick question for you Building Regs experts.

I've got a bit of a tricky one and I've run out of steam arguing with the building inspector. Its a split level house so single storey at front but ground slopes away to rear so it includes a lower ground floor to rear making it 2 storeys. I'm working on a loft conversion and run into problems with the building inspector over the protected staircase. He wants a fire door at the bottom of the stairs on the lower ground floor level but I would rather keep the lower ground floor open plan.

My argument is the final exit is on the ground floor so in the event of a fire people in the bedrooms in the loft will only have to come down one flight of stairs and out the front door. Together with linked mains smoke detectors on all levels and fire egress windows and fire doors on the ground and first floor rooms the proposed layout is no more risky than a standard 2 storey house except to the rear the new first floor is more than 4.5m above the lowest ground level.

I've gone through the relevant determinations and cannot find the exact same circumstances but some similar such as a 3 storey house with an escape route on the first floor which have been allowed. I don't really want to go down the determination route so wondered if anyone here had any pearls of wisdom I could try to convince the pedantic building inspector.

Yes it is local council inspector and yes I know I should be using a private inspector. I wont be making that mistake again.

Thanks.

 

[bernardgreen]

My argument is the final exit is on the ground floor so in the event of a fire people in the bedrooms in the loft will only have to come down one flight of stairs and out the front door.

They can only come down the stairs if the stairs are still there and the smoke has not reduced visibility to make use of the stairs hazardous.

 

[wessex101]

They can only come down the stairs if the stairs are still there and the smoke has not reduced visibility to make use of the stairs hazardous.

Yes, but exactly the same as a normal 2 storey house with an open plan ground floor. The distance to travel to a safe exit is exactly the same.

The only added risk is height of the first floor loft rooms above the lowest ground level to the rear but that is negated by the fact that there is a flat roof extension with roof terrace to the rear so we are back to it being the same as a bog standard 2 storey house (unless the extension is a raging inferno).

I've given the client all the options and I suspect he will come back and agree to the fire door at the bottom of the stairs.

 

[bernardgreen]

The only added risk is height of the first floor loft rooms above the lowest ground level to the rear

Windows in first floor rooms can only be consider as escape routes if they are in a vertical wall and can be accessed by a fire brigade ladder. In general windows in a roof cannot be considered as escape routes because ladders cannot reach them. They may also be fire under the edge of the roof making it liable to collapse or to burn anyone trying to slide down it.

 

[wessex101]

Windows in first floor rooms can only be consider as escape routes if they are in a vertical wall and can be accessed by a fire brigade ladder. In general windows in a roof cannot be considered as escape routes because ladders cannot reach them. They may also be fire under the edge of the roof making it liable to collapse or to burn anyone trying to slide down it.

Thanks Bernard, another very good point but the windows to the rear are vertical in the dormer, in fact they are french doors with a juliette balcony. I realise the potential for a fire in the extension is the one weakness in my argument. To counteract that I offered to put an additional linked smoke detector in the extension but the inspector was having none of it.

 

[tony1851]

@ Wessex; I think your interpretation is correct.

It's not just the number of stories which is relevant, but the height of the floor above ground level. As the floor of the conversion will presumably not be more than 4,5m above ground level at the front, then an open-plan layout should be acceptable, particularly if a person in the loft can go downstairs and straight out of the front door.

If smoke occurred in the lower ground floor, it would present no more of a hazard than it would on the ground floor of an open-plan two-storey layout.

If that was my job, I would advise the client to go for a determination rather than mess up the ground floor, but that's your call.

Memo to Wessex; private inspector every time!!

PS, could you put a Velux-type escape window in the front roof slope?
Remember that the details in the ADs are advisory only. Particularly with regard to fire, it's all down to risk, and reducing it to sensible levels.

 

[chappers]

I agree, maybe say to the BCO that you are going to go for a determination and ask him how he specifically feels that the proposed layout contravenes the building regs/ADs.
Alternatively if you feel that your client has a fair grasp of the risks and how they relate to a normal 2 storey property. then suggest that maybe you install the additional detection, fit the door get the works signed off and then remove it afterwards. Doesn't leave you strictly on the right side legally, but solves a nonsense problem.

 

[wessex101]

Thanks Tony and Chappers.
I'm glad its not just me going mad. I got caught by the 4.5 metre floor height because the ground slopes away to the rear and the rooms on the first floor in the roof space are therefore just over 4.5m from the lowest ground level and I've got velux's in the front roof slope but not escape windows.
I've emailed a set of plans to an approved inspector for a fee quote and asked their interpretation on the means of escape just to give the client a third option to start from scratch with the approved inspector. The second option being to install the fire door at the bottom of the stairs and rip it out as soon as the job is signed off.

 

[tony1851]

The second option being to install the fire door at the bottom of the stairs and rip it out as soon as the job is signed off.

Suggest leaving the decision on that to him because it will at the very least invalidate his insurance, and if the worst should happen.......?
In situations like this, I always say to clients "what some people do once it's been signed off is ...........".

 

[Nakajo]

It may invalidate the insurance. But it may not. I have more or less this arrangement, with no door at the bottom of the stair. The district surveyor (it was a very long time ago) grumbled about it but let it pass. The insurers are aware of the situation, and the house is insured. I suspect the insurers will be more concerned that a properly maintained interlinked fire detection system is provided - but ask them.

 

[wessex101]

Quick update. Just spoke to the approved inspector and he agrees with the local authority. But at least he suggested the alternative of creating fire egress windows on the front/gable elevations so at least being proactive.

His interpretation of the 4.5m height rules was interesting. He took the view that you could drop 4.5m and probably survive even if it meant crawling with minor injuries to a safe distance from the burning house. Any higher and you would do serious damage to yourself and in my case you would land on a flat roof and with say a broken leg you wouldn't be able to make the second jump down to the ground, so you would be trapped on the roof slowly simmering at gas mark 7.

So it is either the fire door at the bottom of the stairs or front fire egress windows in the loft rooms. Interesting little conundrum though and hopefully someone else might find it useful.

 

[wessex101]

Final update, the approval notice came this morning.

We went with a slightly longer velux in the front roof slope (to get the fire egress sill height) for bedroom 1 and a small fire egress window in the gable for bedroom 2 where the floor level is less than 4.5m above the ground level along the side of the property. Bedroom 3 already had a fire egress window to the front so that was OK.

All I've got to do is get an amendment on the planning permission for the window in the gable. Should be OK with obscured glass and it only looks out onto the blank gable wall of the neighbour's house. But I've told client to go and sweet talk the neighbour and explain it is only a fire escape just in case. There are french doors with a juliette balcony on the rear elevation of the bedroom that overlooks the neighbour's garden and that went through OK so I don't envisage too much trouble with this one (famous last words).