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Building extension question 19:06 - Jul 19 with 2105 views

I’m having a single story extension put on my house. Because it has glass either side of the external corners it has a steel frame to hold the roof up.

My question is whether these steel corner posts need to be clad with plasterboard (fire rated or otherwise) or whether it’s OK for the builder to pack them out with wood to get the levels required for the windows, plaster skim etc?

A mate told me they should be covered with fire rated plaster board, but I can see the builder has put wood against one of them. I don’t want to say anything without the being sure of what the regs require. Can’t see anything in regs we’ve got for the job, and can’t find what I’m looking for on line,(apart from something that says single storey steels don’t always need to be lined)

Any of you clever TWTDers know about such things?

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Building extension question on 19:23 - Jul 19 with 2010 views

Nomore4

Have you a structural engineer involved with your job? They would be the ones to answer your question.

Building extension question on 19:43 - Jul 19 with 1967 views

tazdac

I think if you put in rsj’s they should be covered in one layer of fire rated plasterboard or two layers of regular board. Regs may have changed though :o)

(No subject) (n/t) on 19:43 - Jul 19 with 1970 views

tazdac

Building extension question on 19:43 - Jul 19 with 1965 views

wiltshireblue

I can only answer based on my experience and my conversations with my council building regs officer 3 years ago when building my extension

In my case I had to use fire rated plasterboard to protect the steels and create an encasement. I also had to leave this exposed for the building regs officer to see I had done it before I could plaster on top (my understanding now is you can just do photos and upload them to a portal)

Surely you have your local building regs officer who has had to visit or an independent one who will advise on this?. Ultimately once they sign it off that’s the main thing but If you want it done correctly my understanding is it would need to be encased

The only occasion I can think this might not be the case is if you are doing it within permitted development and keeping the original doors partitioning from your main building in which case you might not need to

I’m doing a porch at the mo and because I want to remove my internal door everything needs to meet building regs but if I left the internal door I could near enough make it from
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[Post edited 19 Jul 2023 19:45]

Building extension question on 19:51 - Jul 19 with 1890 views

Nomore4

Building extension question on 19:23 - Jul 19 by Nomore4
Have you a structural engineer involved with your job? They would be the ones to answer your question.

Although my answer without knowing or seeing your job, or what’s been done by said builder is.
Any timber used in packing around the steel would all be covered in fire rated plaster board….ready for plaster skim. It sounds to me the said builder hasn’t got to the stage yet of covering any timber used with fire rated plaster board.

Building extension question on 19:59 - Jul 19 with 1845 views

textbackup

You’ll need fire rated plasterboard, or two layers of 12.5mm normal board, for fire regs

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Building extension question on 20:02 - Jul 19 with 1828 views

Kieran_Knows

When we had our wall removed between kitchen and dining room and had a steel put up, we had to have fire rated plasterboard cladded to the steel. They had to put timber in the C section of steel running along the top so they could fix the plasterboard too, and then they simply just fitted the 2 uprights with screws directly in to the steel.

All was signed off by an independent Building Control company.

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Building extension question on 20:14 - Jul 19 with 1783 views

Nomore4

Building extension question on 19:51 - Jul 19 by Nomore4
Although my answer without knowing or seeing your job, or what’s been done by said builder is. Any timber used in packing around the steel would all be covered in fire rated plaster board….ready for plaster skim. It sounds to me the said builder hasn’t got to the stage yet of covering any timber used with fire rated plaster board.

But as you are building a single story extension with the use of steel beams and no doubt bi fold.
You would have had a structural engineer who would have supplied his engineered drawings for your extension. And local authority building control would have already seen personally at over site stage and any steel beams in situ and returning once roof is on.
So either of them is your go to for questions.

Building extension question on 21:35 - Jul 19 with 1645 views

Vic

Thanks all.

We do have a structural engineer and Ive just found his drawings and think Ive managed to decipher his symbols. It appears that here’s showing the steel corner posts packed out with wood and then clad with plasterboard. So builder is doing it by the book it appears.

I’ve had building work done in the past which has included RSJ’s and always had them double covered with the fire resistant plaste4board, which is why I was concerned at what the builder is doing. But this seems to be a different things so I’d better let him get on with it!

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Building extension question on 21:42 - Jul 19 with 1617 views

Bluestu

All structural steel would require 30 mins fire resistance unless it only supports a roof, in which case you wouldn’t need FR.

Building extension question on 21:57 - Jul 19 with 1589 views

thunderhead

Yes you only need to fire rate elements supporting floor or areas which form part of the means of escape.

Building extension question on 22:01 - Jul 19 with 1564 views

thunderhead

Building extension question on 21:57 - Jul 19 by thunderhead
Yes you only need to fire rate elements supporting floor or areas which form part of the means of escape.

Also depending on the detail, and if the post is exposed you might want to consider insulating around the post internally to prevent cold bridging.

Building extension question on 08:44 - Jul 20 with 1378 views

itfcjoe

Obviously not seen job, and should speak to building regs officer if not sure - but sounds as though they are just getting ready to fit the fire rated board to it by battening it out.

As long as they are encased, the battens inside don't make any difference - and you'll need something to fix the board to

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Building extension question on 09:03 - Jul 20 with 1353 views

Churchman

Building extension question on 19:43 - Jul 19 by wiltshireblue

[Post edited 19 Jul 2023 19:45]

Sounds right to me.

Three years ago our kitchen was extended into half of my very long garage which involved an rsj, new inner walls, rebuilt wall etc etc. it was designed by an architect with of course myself and 5he builder working in the plans that included materials to be used, dimensions, spec. All this went to the LA for approval. Planning permission wasn’t required.

The first inspection was precisely to check the fire proofing, damp proofing, roof and all that were correct and was actually done with a camera phone as it was the height of lockdown. There were subsequent visits including sign off. The inspector mush really did look art the drains, mains wired fire alarms, fire doors including strips you name it. He was pedantic!

Whilst annoying, the work is signed off and that’s the key - make sure you are covered on building regs.

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