Filling in around base of vertical structural steel beam

[Chanmenie]

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 ?

[JohnMo]

I just painted mine with bitumen paint, if zoom in you can see what I did.

 

 

[Mr Punter]

2 hours ago, Chanmenie said:

cement/concrete corrode the steel

 

Not at all.  Concrete will protect the steel from corrosion.

[markc]

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

[Chanmenie]

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.

[markc]

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.

[Chanmenie]

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 

[markc]

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

[Simplysimon]

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

[Chanmenie]

Yeah I can insulate it where the concrete slab is going but it’s a bit late to put armatherm under it

[Chanmenie]

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 ?

[markc]

The amount of heat transfer by the studs and post base will be very small

[Radian]

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.

[Mr Punter]

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.

[Tom]

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

[markc]

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

[Tom]

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

[Chanmenie]

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

[Tom]

I bought two pieces about that size and it came to about £100 iirc

[Chanmenie]

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 

[Tom]

Yes! Especially as I only needed one piece but the minimum order possible was £100!

[markc]

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.

[Tom]

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

 

 

[markc]

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

[Tom]

Aha! Definitely an opportunity there, tap in to the neurotic-self-builder market...