I’m looking at buying a house that has a mezzanine (approx 14 feet long and 52 inches wide). It’s currently around a foot too narrow to fit a sofa bed across it (which we’d like to have for guests as the house is three bed compared to four at the moment). Also considering putting up a stud wall instead of the railing but with ‘windows’ to match the existing ones and then with blinds inside for privacy (family don’t live locally so we often have them over for a week at a time).

Does anyone know how complex/etc it would be to extend the mezzanine out by around a foot? I don’t think planning permission would be needed as it’s internal and won’t be a habitable room but worst case, I can see that it might require a steel beam or similar across the room.

(this pic makes it look quite narrow but it is over 4 feet wide)

We won’t be keeping the sofa 🙂

my in-laws have a similar mezzanine and it isn’t wide enough for a bed as it comes under the building regulations for a bedroom if it did.

Surely only if you’re actually trying to claim it as a bedroom?

not sure, but when I said you should have made that wider, the response was we would have if it hadn’t got a lot more expensive and complicated…

Maybe I need to talk to a planning officer…

I’m not an expert but i would think it would be easier to take it down and start again?

However you could reuse the stairs and balustrade and most of the flooring. Pretty sure it would just be all the structural parts that would need increasing by a foot in length so to speak.

However looking at the picture am I correct in saying it is all timber? Although you are only extending by a foot would the timber joists be strong enough at their current size? You would also need to replace the wall plates at either end.

My advice would be to get an engineer to look at it as you don’t want the new extended one being bouncy or falling down!

If you have the room at the foot of the stairs – just take the stairs and front down, move the front beam forward, install new joists, fit flooring.
Simplez.
It is as easy or as complicated as you want to make it.

I’ve just been told by the planning dept that because there’s no change to the exterior, it would be building regs only.

It does look like it’s all timber at the moment. Taking it down and restarting from scratch would certainly be an option depending on the structural calcs.

I should probably add that my present thinking is that I would move the stairs to the mezzanine from where they are at present to where the sofa (eg turned 90 degrees, going from the bottom on the right to the top at the left of the pic).

Building control say that it just needs to conform to the normal regs for a mezzanine if I extended it. I need to find out whether there’s any limitation on size (that jambo suggests) though I haven’t seen anything like that so far.

Something for your consideration and based purely on your photo, is that if you increased the width of the mezzanine and moved the stair access by your preferred 90 degrees, looking at the pitch of the roof, would you have the required head clearance from finished floor level at the top of the stairs to the underside of the exposed ‘purlins’ (longitudinal beams)? From vague memory, this needs to be at least 1.85mtrs, but could be more.

Good question. I think so but it wouldn’t be a million miles off.

“Also considering putting up a stud wall instead of the railing but with ‘windows’ to match the existing ones and then with blinds inside for privacy (family don’t live locally so we often have them over for a week at a time).”

this will ruin the aesthetics of the house in that photo.

Maybe though the intention is to make it much more modern that it looks there and I reckon it would be ok. Just an idea at present and let’s face it aesthetics is going to be hard to quantify.

Get them to sleep end to end. Problem solved, I’ll send my invoice presently.

Would dominate the room a bit, especially if closed off with stud wall, even to balustrade height

I had considered that 🙂

I suspect that door opening on the left is going to impact your plans a little. Are you looking to go out further than that?

No – really just a foot, foot and half – enough to allow a sofa bed. And that might not even be the full length of the mezzanine – possibly just one section of it.

Wang in an extra joist then. Prop up with acros, get a plasterer to clad said acros with some plasterboard, skim, paint. Extend floor. Bosh.

Possibly… would be nice to do it without needing any supports though. I did note that at present there’s only one joist (the one you can see) which suprised me slightly.

Apologies, was just taking the mick.

Is there not another joist against the wall? Surely there is a way of getting another joist in? The two in there look beefy enough for that span…though (embarrassingly), I’m not au fait with present regs regarding spans sizes, etc. (it’s all builders’ stuff really). Personally, if I got a third joist in, I’d plasterboard the underside, get some spots in perhaps. Might help modernise it a bit if that’s what you want.

EDIT: And possibly take out the balustrade altogether and stud wall it – which would make sense if you’re putting a sofa-bed in there.

The only reg that really seems to limit the size is to say that the mezzanine (including the stairs’ footprint I believe) mustn’t be more than 50% of the main room’s area which isn’t going to be an issue for the size I’m looking at.

Fire regs are the main issue as it’s considered habitable but that should be ok with a fire escape approved window.

Ideally sticking another joist across (you’re right, there’s one against the back wall as well as the one you can see) and extending the floor would do the job and would be the simplest solution.

What length is it wall to wall?

The width across (left to right in the pic) is 14’8″

14′ 8″ hang on let me just get my converter out 😉

4470mm. Ill be back shortly.

Rough “guess” you’ll need a 9×2 c16 grade timber. 100mm bearing either side as I presume this is what’s already there and how its done? Are there any 4×2 say hung off the two main timbers running at 90 degrees?
However I have an engineer to do this for us!

A bit of gripfill will hold it up won’t it?

EDIT: depends on the thickness of the plasterboard on the wall I suppose.

9×2 – is that inches? That certainly sounds pretty close to the joists that are there. There aren’t any joists at 90 degrees as far as I could see – just the two main joists with board on top.

Which direction are the boards running? I’d be surprised if there were no noggins there.

Can’t see – they’re plastered (I would assume 90 degrees to the joists though)

I don’t think that there are noggins – from underneath, there are the two joists and then what looks like the underside of the floor (plastered over), assuming from the height that there’s no significant woodwork between the floor and the plaster.

Oh right, I would have thought they’d run cross members between the two main joists and then run the floorboards parallel with the length of the mezzanine. As you were then.

Shirley if you put a wall up it will then become a habitable room? With regard to sealing it up when guests are using it you could put a number of pegs along the side of the beam above where your new balustrade would be. Get some heavy curtain material and essentially create a fabric wall when required. Then you can just fold it up and pop it in the cupboard when they leave. I’ve seen it on a grand designs thingy where it looked good but i fear my description makes it sound pants 🙂

I meant a stud wall at waist-ish height.

Just run another joist [same size as the current ‘outboard’ one] at the width you want and move the stairs out to fit.
Plastering underneath sounds like a good idea especially as the new joist will look odd.
I’d get rid of the balustrade (looks like a tea room) and go with a partition wall the same height – or glass.
Think twice about making changes for the family who only visit a few times a year – you have to live with the place so make it look how you want it. Temporary privacy can always be added quickly and easily with a curtain hung on hooks and removed the rest of the time.

It’s already a habitable area.

Darcey you know my skills well!
I also thought the flooring would run with the main timbers as 1200 is a fair old span! If its chipboard you better not spill any water up there 😉

As an extra thought as the stairs are off it I’d double up and coach bolt the two lengths together.