Chanmenie Posted September 16, 2022 Share Posted September 16, 2022 I have a pair of goal post vertical steel columns coming up from the foundations, they will be bolted to the concrete footings. They will be boxed in with shuttering to enable completion of the ground build up with insulation, UFH and the pour of the concrete slab. Once this is completed and the ICF walls built up, how should I fill in around the columns up to finished floor level, will cement/concrete corrode the steel ? Link to comment Share on other sites More sharing options...
JohnMo Posted September 16, 2022 Share Posted September 16, 2022 I just painted mine with bitumen paint, if zoom in you can see what I did. Link to comment Share on other sites More sharing options...
Mr Punter Posted September 16, 2022 Share Posted September 16, 2022 2 hours ago, Chanmenie said: cement/concrete corrode the steel Not at all. Concrete will protect the steel from corrosion. 1 Link to comment Share on other sites More sharing options...
markc Posted September 16, 2022 Share Posted September 16, 2022 (edited) As above bituminous paint is good (especially where the steel exits the concrete). Steel fully covered in concrete is left bare (re-bar) with no concern for corrosion. Edited September 16, 2022 by markc Link to comment Share on other sites More sharing options...
Chanmenie Posted September 16, 2022 Author Share Posted September 16, 2022 Thanks guys, do I need to be careful of condensation forming on the steel ? and what about fire protection, it’s a chalet bungalow so technically single storey but the beam is holding up the gable end. I had a look at Doc H but could not work out what’s required as single story. Link to comment Share on other sites More sharing options...
markc Posted September 16, 2022 Share Posted September 16, 2022 Condensation really depends where the steel is, if fully inside the warm envelope then condensation will not be a problem. And steel will stand up to fire better than timber trusses etc so no need for fire protection. Link to comment Share on other sites More sharing options...
Chanmenie Posted September 16, 2022 Author Share Posted September 16, 2022 36 minutes ago, markc said: Condensation really depends where the steel is, if fully inside the warm envelope then condensation will not be a problem. And steel will stand up to fire better than timber trusses etc so no need for fire protection. Yeah the columns and beam are within the warm envelope other than where it’s bolted to the strip footing concrete So ok to just box it in with plasterboard Link to comment Share on other sites More sharing options...
markc Posted September 16, 2022 Share Posted September 16, 2022 5 minutes ago, Chanmenie said: Yeah the columns and beam are within the warm envelope other than where it’s bolted to the strip footing concrete So ok to just box it in with plasterboard If you are boxing in with PB then you are keeping it warm and fireproofed Link to comment Share on other sites More sharing options...
Simplysimon Posted September 16, 2022 Share Posted September 16, 2022 25 minutes ago, markc said: you are keeping it warm apart from the heat leaching in a cold bridge to foundations! armatherm or similar should be placed below steels and insulation around where concrete is going to be placed Link to comment Share on other sites More sharing options...
Chanmenie Posted September 16, 2022 Author Share Posted September 16, 2022 Yeah I can insulate it where the concrete slab is going but it’s a bit late to put armatherm under it 1 Link to comment Share on other sites More sharing options...
Chanmenie Posted September 17, 2022 Author Share Posted September 17, 2022 10 hours ago, Chanmenie said: Yeah I can insulate it where the concrete slab is going but it’s a bit late to put armatherm under it @Simplysimon, Having said that, the studs I have resined into the concrete are 30mm longer than required so if Armatherm or an alternative is available in 30mm I assume that would be better than nothing ? Link to comment Share on other sites More sharing options...
markc Posted September 17, 2022 Share Posted September 17, 2022 The amount of heat transfer by the studs and post base will be very small Link to comment Share on other sites More sharing options...
Radian Posted September 17, 2022 Share Posted September 17, 2022 13 hours ago, markc said: Condensation really depends where the steel is, if fully inside the warm envelope then condensation will not be a problem. And steel will stand up to fire better than timber trusses etc so no need for fire protection. The problem is that steel becomes more ductile at elevated temperatures so it doesn't have to melt to be unable to take it's loading. Link to comment Share on other sites More sharing options...
Mr Punter Posted September 17, 2022 Share Posted September 17, 2022 14 hours ago, Simplysimon said: armatherm or similar should be placed below steels The trouble is lack of availability. Where can you easily buy this? Is there an actual stockist in the UK? Also, to get this to work it would need to be fitted at the same time as the steels or slipped underneath. Normally I just see the base plates shimmed with steel and filled under with structural grout. 1 Link to comment Share on other sites More sharing options...
Tom Posted September 17, 2022 Share Posted September 17, 2022 we used some armatherm to sit a vertical steel on. Ridiculously expensive for what it is really and will probably make no difference to anything other than my wallet 1 Link to comment Share on other sites More sharing options...
markc Posted September 17, 2022 Share Posted September 17, 2022 1 minute ago, Tom said: we used some armatherm to sit a vertical steel on. Ridiculously expensive for what it is really and will probably make no difference to anything other than my wallet True, and if you had holding down bolts or rods then there is no point trying to isolate the base Link to comment Share on other sites More sharing options...
Tom Posted September 17, 2022 Share Posted September 17, 2022 you get little washers made of the same stuff to use to reduce the bridging with the fixings, but of course can never fully eliminate it Link to comment Share on other sites More sharing options...
Chanmenie Posted September 17, 2022 Author Share Posted September 17, 2022 (edited) 16 minutes ago, Tom said: you get little washers made of the same stuff to use to reduce the bridging with the fixings, but of course can never fully eliminate it What does call ridiculously expensive @Tom ? I only have two steel columns the base plates are 350mm x 250mm, they sit inside the external walls Edited September 17, 2022 by Chanmenie Link to comment Share on other sites More sharing options...
Tom Posted September 17, 2022 Share Posted September 17, 2022 I bought two pieces about that size and it came to about £100 iirc Link to comment Share on other sites More sharing options...
Chanmenie Posted September 17, 2022 Author Share Posted September 17, 2022 6 minutes ago, Tom said: I bought two pieces about that size and it came to about £100 iirc That seems rather a lot for what it is Link to comment Share on other sites More sharing options...
Tom Posted September 17, 2022 Share Posted September 17, 2022 Yes! Especially as I only needed one piece but the minimum order possible was £100! Link to comment Share on other sites More sharing options...
markc Posted September 17, 2022 Share Posted September 17, 2022 I think this is very like being anal on air tightness and then opening a door every few hours for visitors or Amazon (other delivery services are available) parcels. yes build well but don't overspend on something that makes very little difference. Link to comment Share on other sites More sharing options...
Tom Posted September 17, 2022 Share Posted September 17, 2022 Sure, but being pragmatic I guess it's not just about overall thermal performance. Cold bridging in certain areas/circumstances might lead to condensation, corrosion etc Link to comment Share on other sites More sharing options...
markc Posted September 17, 2022 Share Posted September 17, 2022 3 minutes ago, Tom said: Sure, but being pragmatic I guess it's not just about overall thermal performance. Cold bridging in certain areas/circumstances might lead to condensation, corrosion etc Absolutely, but you will probably end up with cold bridges around a house anyway, door handles is the most common as the handles are metal and the turn bar is one piece of steel. Very few door handle sets are thermally broken 1 Link to comment Share on other sites More sharing options...
Tom Posted September 17, 2022 Share Posted September 17, 2022 Aha! Definitely an opportunity there, tap in to the neurotic-self-builder market... 1 Link to comment Share on other sites More sharing options...
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