Building regs for "semi-basement"

[Trebby]

Hi,

Hoping there are some building regs experts on here...

We have a Victorian house that is built into the hillside and has a lower ground floor. This is accessed by a staircase from the main hallway on the ground floor. There are several rooms on this floor, and the lower ground floor has a backdoor that leads to the back garden - I think it is described as a "semi basement". There is an original room at the rear of the house that has windows looking onto the back garden. At the front of the house and directly in front of the original room is another room that we would like to convert. This has a wall that is a bit damp as it sits in the hillside (but is not actually wet and no water has ever come through) and has a very small window in a light-well

We have had a few specialist basement companies around who have all said conversion is feasible, probably with a damp proof membrane and no need for a sump pump. The question I have is about building regs which the companies have had differing thoughts on. Most of them said that building regs are not required as there are already rooms on the same level that are classed as habitable rooms, but one said that we would need to put in a large window as a fire escape into the room, despite there being several methods of exit from the floor itself.

I've extensively searched and not found any identical questions, and I'd be really grateful for other opinions. It's really important to us that this adds value and that it can be classed as a "habitable room" when we sell.

Thanks in advance.

 

[lt8480]

It is hard to know whether building regs is required as it depends on the work to be undertook, and not whether there are already rooms on the same level that are habitable.

I'd speak to an approved inspector, if it doesn't need sign off they should tell you. But the requirement/obligation to get sign off if required is your responsibility and not the builder so you can't blame them later if you don't do it and it should have been done.

If clearly not habitable now, and intending to make habitable though I would guess it would require sign off.

BRegs for Fire is part B vol 1: https://assets.publishing.service.g...chment_data/file/485420/BR_PDF_AD_B1_2013.pdf

Your new room in an "inner room" - i.e. it does not have direct escape out and you have to pass through another space. The only way this would be acceptable is listed in 2.9. In summary it would need to be either a kitchen, laundry, utility, dressing room, bathroom, wc, or shower room. If not one of these uses then it need to have an egress window as per 2.8.

Alternative you may be able to provide a door into a hall and a door into another room (basically so you have two exits from the room), see Diagram 2. B page 17. But you will also need to check you have fire separation.

If to be used as a habitable room then a large window may be a good idea anyway. Digging out a front light well will have cost and probably require planning, but may also help reduce damp and in general make the room nicer and more valuable.

It is concerning the many specialist basement companies are wrongly advising / guessing on regulatory requirements... perhaps they do not want their work inspecting?

On a side note a membrane is only as good as it is detailed and fitted (often not good).

 

[^woody^]

Converting a basement to a habitable room requires building regulation approval. Then the various matters come into play in terms of fire safety, escape, waterproofing etc.

Bear in mind that however good the waterproofing system, and however skilled the workers, the system will fail. That is why all installers should not be saying that a sump pump is not required. And surveyors at sale time will be advising their clients on this basis.

 

[Leofric]

As woody says you require building regs approval so I would advise preparing and submitting a full plans submission for approval before work starts on site.
p.s . I wasn't aware that basement waterproofing was bound to fail , but building rooms below ground level is always a bit of a risk in my opinion.

 

[^woody^]

As woody says you require building regs approval so I would advise preparing and submitting a full plans submission for approval before work starts on site.
p.s . I wasn't aware that basement waterproofing was bound to fail , but building rooms below ground level is always a bit of a risk in my opinion.

If should be considered as part of the site appraisal and risk assessment. It will fail so the disruption of that and repair/renewal should be allowed for - which typically means a design of a drained cavity and pump as a back up. In some cases it can mean allowing for a reserve pump if the main one should fail too.

The crucial thing is that no designer/supplier/installer should be saying straight off that a pump is not required.

 

[Trebby]

Thank you all for the helpful replies. That's very useful. I think I'll get some quotes from other companies regarding cost for conversion which meets building regs and then decide whether to proceed at all.

Thanks again.

 

[Leofric]

So you will be relying on builders to decide what is required to comply with bldg. regs. Might be a problem that they could all have different ideas. Anyway, without approved plans they are only likely to give an estimate rather than a fixed price quotation. If an egress window is required ,a means of escape to a place of safety away from the building, i.e. a fire escape stair up to ground level, would be required; but impossible to say what is required without knowing all the relevant details of the building.