Super_Paulie Posted August 19 Share Posted August 19 Evening. I'm plasterboarding my gaff but I have this thing I need a bit of advice on. The main steel beam is supported on one side with an upright tubular steel beam which is within the inner block work. It's got wool behind it in the cavity, if the builder built it to my architects drawing. The other side rests on a pier. Anyways I want to plasterboard over this wall but do I need to do anything additional to the beam? I suppose warm air will travel through the plaster and hit the steel which I'd imagine would be significantly colder in winter. The beam goes down below joist level and it's a suspended floor, ie, cold. I sadly can't board this wall with insulated board as the builder made the return at the door very small so I can't lose the room and still fit in my 600mm units. Any suggestions? Link to comment Share on other sites More sharing options...
Onoff Posted August 19 Share Posted August 19 A strip of Aerogel insulation perhaps? 1 Link to comment Share on other sites More sharing options...
bassanclan Posted August 19 Share Posted August 19 It doesn't look like it has even been primed? Link to comment Share on other sites More sharing options...
Super_Paulie Posted August 19 Author Share Posted August 19 6 minutes ago, bassanclan said: It doesn't look like it has even been primed? Think it's just raw steel, yeah. Building inspector didn't say anything so I guess he's happy. Just need to address the potential cold bridge, I'll look into aerogel now. Link to comment Share on other sites More sharing options...
ETC Posted August 19 Share Posted August 19 Do you need fire protection to the steelwork? 1 Link to comment Share on other sites More sharing options...
Super_Paulie Posted August 19 Author Share Posted August 19 4 minutes ago, ETC said: Do you need fire protection to the steelwork? Inspector never suggested fire protection on this upright as far as I'm aware. Link to comment Share on other sites More sharing options...
saveasteading Posted August 19 Share Posted August 19 Are you fixing battens or dot and dabbing? Both will create an air gap which adds insulation. You could add a strip of eps over the prop. Battens are better and also reduce heat circulaion in the small void and aid insulation a bit more. Does the beam need fire protection? Unlikely. In the unlikely event of a 300° rise in temperature you won't be in there. There's no room above is there? Link to comment Share on other sites More sharing options...
Super_Paulie Posted August 19 Author Share Posted August 19 I was going to fasten directly with foam, to stop a bridge an adhesive dab would bring. I don't have room for battens unfortunately. The vertical beam is supporting the main beam which supports the cavity wall above. I would just use fireboard over the vertical, no biggy. It's the cold bridge I'm looking into, but maybe with insulation in the cavity behind the vertical steel it won't be an issue? Link to comment Share on other sites More sharing options...
saveasteading Posted August 19 Share Posted August 19 1 minute ago, Super_Paulie said: fasten directly with foam Can't 1 minute ago, Super_Paulie said: beam which supports the cavity wall above. I would just use fireboard over the vertical, no biggy. If the beam failed, what else comes down? No biggy? Its often a bit more complex than that. Link to comment Share on other sites More sharing options...
Super_Paulie Posted August 19 Author Share Posted August 19 I can't use plasterboard foam on the walls, how come? I was going to just foam on and throw in a few mechanical fixings. I've already done all the internal walls as such. Id imagine the entire house would fall down if the beam failed seeing as it supports the main beam 😆 Link to comment Share on other sites More sharing options...
crispy_wafer Posted August 20 Share Posted August 20 Love the smilies in the backboxes... Can I ask how you cut, and set the backboxes in the blocks, I'm about to embark on this and am looking at various methods, while I pluck up the courage to go for it! Link to comment Share on other sites More sharing options...
saveasteading Posted August 20 Share Posted August 20 8 hours ago, Super_Paulie said: the entire house would fall down So you need to protect it, whether or not the bco has thought about it. If you have had this professionally designed, speak to them. Boxed in 2 layers of ordinary plasterboard is best. Otherwise lots of intumescent paint and special top coat. Link to comment Share on other sites More sharing options...
Super_Paulie Posted August 20 Author Share Posted August 20 (edited) 58 minutes ago, saveasteading said: So you need to protect it, whether or not the bco has thought about it. If you have had this professionally designed, speak to them. Boxed in 2 layers of ordinary plasterboard is best. Otherwise lots of intumescent paint and special top coat. Why couldn't I just use plasterboard adhesive foam with additional mechanical fixings, a fire rated plasterboard and just continue along the wall? Id just use a fire rated board where it passes over the steel and normal boards elsewhere, I guess a full fire board would give me 450mm either side of the post that would also be fire protected. It's the vertical, tubular post we are talking about here, not sure if you're thinking about the horizontal beam which is to be left exposed and painted with intumescent. Edited August 20 by Super_Paulie Link to comment Share on other sites More sharing options...
Super_Paulie Posted August 20 Author Share Posted August 20 2 hours ago, crispy_wafer said: Love the smilies in the backboxes... Can I ask how you cut, and set the backboxes in the blocks, I'm about to embark on this and am looking at various methods, while I pluck up the courage to go for it! Yeah, smiley protection covers 😆. I stitched them out with an SDS and used the SDS chisel to take them back to depth. I mortared the boxes in to keep them tidy, deep boxes all round. 1 Link to comment Share on other sites More sharing options...
Super_Paulie Posted August 20 Author Share Posted August 20 2 hours ago, saveasteading said: So you need to protect it, whether or not the bco has thought about it. If you have had this professionally designed, speak to them. Boxed in 2 layers of ordinary plasterboard is best. Otherwise lots of intumescent paint and special top coat. Hopefully his is a bit clearer. Other than aerogel i guess my options are limited, but as the steel is within the inner leaf, ie insulation behind it in the cavity, then cold bridge will hopefully be minimal. Link to comment Share on other sites More sharing options...
kandgmitchell Posted August 20 Share Posted August 20 I can't see that post being a significant issue for fire, it's heated perimeter related to it's section size is small. The other faces are protected by the blockwork either side and the cavity and external leaf. It's also well stabilised so if heated to a point of failure it'll be held in position. The beam is at far more risk from failure in a fire and will tend to pull the post away from the wall as it sags. I would have thought a strip of fire resistant board against the post itself and then a panel of board across it in the plane of the plasterboard would be plenty. If there's room for some aerogel as well it'll help the cold bridge effect. 1 Link to comment Share on other sites More sharing options...
saveasteading Posted August 20 Share Posted August 20 2 hours ago, kandgmitchell said: . The beam is at far more risk from failure That's what I meant. Link to comment Share on other sites More sharing options...
Super_Paulie Posted August 20 Author Share Posted August 20 yes the main beam is to be protected with the appropriate paint. Anyways, its the thermal element i was really looking for advice for on that upright beam. I think there are no options that suit my application other than aerogel, so thats what i'll go for i think. Link to comment Share on other sites More sharing options...
Super_Paulie Posted August 30 Author Share Posted August 30 To put this to bed, BC said they are happy with standard plasterboard and skim over this vertical and I went with a strip of 10mm aerogel to reduce the cold bridge from the steel. 1 Link to comment Share on other sites More sharing options...
Andehh Posted August 31 Share Posted August 31 Tidy job! Link to comment Share on other sites More sharing options...
Onoff Posted August 31 Share Posted August 31 Good idea that Aerogel 👍 Link to comment Share on other sites More sharing options...
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