Exposed RSJ

[creamcheeseandlox]

We are currently having our kitchen/diner room and playroom knocked into one big family room and the engineer came round today to do calculations etc. We need a rsj to run the width of the ceiling in the middle where a wall was. Our builder said we can either have it sunk into the ceiling which is a two day job as he'll have to relocate pipes wires etc and cut Into the wood joists etc or have it under the ceiling and boxed in. Me and dh looked at some pics of keeping it exposed and made a feature of and painting it dark gray to match the bi fold doors we are having put in. What's the general consensus about it. I actually really like the idea of it...plus it will save us some money. I have attacked some pics to show u how how it could look.

We're planning to do the same. I've found loads of pics on Pinterest and think it can/will look fab.

You can always box it in later if you change your mind.

I've just been doing some reading online about it and it seems that in order to pass building regs if left exposed they need special fire resistant paint on them as otherwise they are at risk of collapsing if heated to a certain temp. Anyone know anymore about this?

You will need it fire proofed to pass building regulations. This can be by boxing in with plasterboard or by the use of intemescent paint. The paint will need to be very carefully applied to ensure it is sufficient for the required fire protection.it will also need to be painted before it's installed to ensure its completely covered. And damage to the paint during the installation of the steel would then need to be touched up afterwards. Hope this helps!

When heated during a fire, the steelwork will relatively quickly lose its structural integrity. Intumescent paint will swell up in the event of fire and keep the steel temperature below the critical temperature - in your case it would need 30 minutes fire resistance.

You will need to provide building control with a 'certificate of supply'.

We had a steel beam in our new build and it got left as it was by the chippies/plasterers. I asked if it could be a 'feature' and was told it was too late to paint it and it had to be boxed in to pass building regs. Chippies were surprised by that, as it's a timber framed house and will surely burn quicker than the steel beam? Anyway it's now all covered up.

Pink panda and assume that once it's all plastered and painted it's quite unobtrusive? Our builder has quoted £700 to sink it flush into the ceiling (labour & relocating pipes, electrics etc plus cost of 12ft steel). So we may have to have it boxed.

I don't dislike the look of an exposed beam but this current fashion for the industrial look will pass and in ten years time, I'll wager it will look very dated / unfinished. I would box it in, and not worry too much about the ridge on the ceiling - it can be an effective way of defining zones in your new space.

If you have nice high ceilings and can carry off the industrial look and have some exposed brickwork etc I think the exposed beam looks great. Otherwise, not so much.

Agree with kiroro and think the pics illustrate it very well. Looks great in the second pic, less succesful IMO in the first.

I agree, I think it really depends on the space (high enough ceilings) and how you're planning to design the space and whether you can "pull off" the industrial / warehouse look. Those photos look great with the very big space, exposed brick wall, very minimalist kitchen design etc so it works. If you're extending a 3 bed semi in surburbia (thats us!) then it will be tricky to get it right and I would box it in.

I also think if you do have it exposed, and painted dark grey, it will be "a feature" - your eye will be drawn to it when you enter the room. If you're having bi-folds and have maybe a lovely view of the garden, it would be a shame that the first thing you end up looking at is the RSJ (just my opinion though!).

I had mine raised into the ceiling, but in a much smaller space - about 11ft x 11ft.
My builder didn't want to do it and said it would cost more as more work for him, but given the space it would have been very intrusive and I told him I wasn't having the extension at all if it couldn't be level with the ceiling.

My friend had previously had a much bigger extension, kitchen / living / dining and hers is boxed in as didn't think about alternatives - when I had mine done she said she wished hers had been done in the same way.

Mine was an extra £500 on a £10k build, so fairly minor in relation to overall cost.

That's a good point. For £600 on a 24,000 build it's hardly more expense. I think we'll get it hidden.

That's a good point. For £600 on a 24,000 build it's hardly more expense. I think we'll get it hidden.

I think this is the right call.

There will be lots of these little decisions that bump up the cost, but worth doing it as well as you can if the money allows.

One of my favourite pictures - steel is often not as good as timber in a fire believe it or not! You can also design the steel beams for loss of strength during a fire to avoid boxing in or intumescent paint, you just end up with a larger steel beam, and it is more involved design, so will cost more.

Didn't like my picture for some reason

Oh it did, oops.

It really loves the pic now

curiously, the steel beams in the pic have been put the wrong way up, so they wouldn't have worked properly even before the fire.

but yes, steel loses strength very quickly when heated. hence blacksmithing and WTC collapse.

Yes - the mangled steel beams at the 9/11 museum are incredible.

PJ, I'm guessing they turned over during the fire maybe. It's a bit odd anyway - why would you have a timber beam under steel beams like that? I have tried to find more details of what actually happened in that picture in the past but without much luck.