Intumescent paint for protecting beams

[MJNewton]

My single-storey extension has got a pair of steel beams over the knockthrough but they are recessed to facilitate a level ceiling throughout. I am now pondering what the best way to fireproof them is.

 

My options identified so far are 1) two layers of plasterboard (can one of these be the ceiling itself?), 2) one layer of fireboard, or 3) intumescent paint. I am leaning towards the latter as there is limited clearance and space for affixing suitable noggins and the boards themselves.

 

Does anyone have any comments/recommendations regarding the paint? I am assuming given the red oxide primer it should be just a case of applying it to all exposed surfaces and that's that?

 

Edited September 20, 2018 by MJNewton

[PeterW]

Just use one layer of fire line and be done with it. No need to do anything else as the ceiling is seen as the fire compartment anyway. 

[MJNewton]

It's how I attach the fireline that could be the challenge as I am assuming it cannot be stuck in place with adhesive?

[Russell griffiths]

A trick we used to do

if you score plasterboard like normal and snap it ready to be cut. BUT. 

Dont cut through it, you can fold it up like a 3 sided box and slip it up from below and hold it in place with the ceiling sheet

 

hope that makes sense 

[MJNewton]

It does make sense; is it held securely?

 

I think I need to get up close and personal with the beams when I get a chance and see what possibilities there might be.

[PeterW]

Just glue it on - no problems doing that. 

[Russell griffiths]

We used to noggin out the beam roughly, tack it to that and intumescent sealer on the corners, then board over it with your ceiling board. 

Its a load of crap really just to keep bc happy. 

[MJNewton]

I'll see what I can do. Thanks everyone for the ideas.

[Mr Punter]

The paint is really expensive and you have to coat it lots.  Doesn't' the ceiling give it 30 mins anyway?

[MJNewton]

For the amount I'd need it'd only be £20.

Edited September 20, 2018 by MJNewton

[Russell griffiths]

If you have done your sums right for £20 I would just paint it

 

but to be honest I don’t believe it

if it was that cheap everyone would paint them, and very few do. 

[Nickfromwales]

14 minutes ago, Russell griffiths said:

If you have done your sums right for £20 I would just paint it

 

but to be honest I don’t believe it

if it was that cheap everyone would paint them, and very few do. 

Also, wtf is a coat of paint going to actually do in a fire? Heat will twist the steel into knots, paint or not, and by the time you’re going to be asking that question you’ll be rebuilding the house anyway so just whack the paint on, enjoy the 30mins ‘get out safe’ time the PB and plaster will afford you and move on with that option if BCO is ok with it  

[Ian]

13 minutes ago, Nickfromwales said:

Also, wtf is a coat of paint going to actually do in a fire?

Intumescent paint expands in a fire and forms a protective layer over the steel that insulated the steel from the heat & flame.

[MJNewton]

27 minutes ago, Russell griffiths said:

If you have done your sums right for £20 I would just paint it

 

but to be honest I don’t believe it

if it was that cheap everyone would paint them, and very few do. 

 

If 4.2m is my length I've got roughly 0.7m width of exposed surfaces so that's ~3m². A litre of Envirograf EP/FS/INT should cover 10m².

 

All said and done though I think I'm leaning more towards the boarding now if I can get it sorted without too much of a headache. It feels a bit more predictable in its performance, as is often the case with more conventional methods.

[PeterW]

You’ll also need primer as it’s for bare steel so that’s another £20... a sheet of fireline is £12 and it will need to be boarded and skimmed anyway so why not just do it to start with ..?

[MJNewton]

It's already primered so I think it can go straight on.

 

It's not really a cost issue; more what was going to be easiest in this particular situation.

Edited September 20, 2018 by MJNewton

[PeterW]

19 minutes ago, MJNewton said:

It's already primered so I think it can go straight on.

 

It's not really a cost issue; more what was going to be easiest in this particular situation.

 

So how are you expecting to finish it or is the plan to leave exposed ..?  I’m confused ..!

 

And those products need their own primer if it’s been painted with something else first. It’s in the MIs

[MJNewton]

45 minutes ago, PeterW said:

 

So how are you expecting to finish it or is the plan to leave exposed ..?  I’m confused ..!

 

The beams are recessed and contained entirely within the ceiling void.

 

Quote

And those products need their own primer if it’s been painted with something else first. It’s in the MIs

 

It was this from the Application Instructions that made me think otherwise:

 

Quote

If a primer has already been applied and is sound, then there is no need to apply Envirograf® primer.

 

Edited September 20, 2018 by MJNewton

[PeterW]

So if it’s in the ceiling just swap to fireline board if your worried and just skim the lot. 

[MJNewton]

I'm not overly worried; as Nick said if there's a beam-twisting fire going on I'll be out of there in a flash and chances are it's a complete rebuild anyway from that point.

[nod]

4 hours ago, MJNewton said:

It's how I attach the fireline that could be the challenge as I am assuming it cannot be stuck in place with adhesive?

Shot fire some top hat metal or a length of cieling track and over board the whole cieling Returning the fire check up the face of the beam

[MJNewton]

Shot fire? 

 

Overboarding is a challenge in this house as the ceilings are suspending on resilient bars (for noise reduction) and finding them with screws without finding the joists can be tricky! 

[Nickfromwales]

11 minutes ago, MJNewton said:

Shot fire? 

Big nasty gun that fires short nails into steel. Dont point at your foot lol. 

[MJNewton]

Ah okay! Not got one of them; sounds fun though. 

[nod]

3 minutes ago, MJNewton said:

Ah okay! Not got one of them; sounds fun though. 

You can hire one for a day