Location of steels and insulation

[Tetrarch]

I'm not sure if this belongs here or in the insulation section.

My architect has prepared my BC drawings:

 

I would like:

 

The rear horizontal beam (outlined in red) to be closer to the rear facade

 

The right rear corner to be smaller in cross-section

 

The internal cross beam supports (circled in green) to not intrude into the room. I can live with the right if required, the left is a real problem with the kitchen units.

 

Notes: The grey wall on the left is solid brick and on the right a cavity wall (from a 1970's extension)

 

 

My architect has replied to all of these with  "possible condensation through the steel because insufficient steel cover".  Do I have any choices here that I might suggest to my architect?

 

Regards

 

Tet

[Kelvin]

You can insulate them. Some people box around them and then fill space with foam. You can also mount the steels on thermal bridge breaking blocks to lift them off the concrete. If you have enough space you could fit 25mm PIR on the outside wall side of the steel on the left allowing you to move out of the room. This is more or less what I did. 

[saveasteading]

Physics is a pain.

If that is a sliding door then the beam has to be very deep and stiff, or it will deflect and the doors stick. Let's see how it is designed.

The top right column needs to be bigger , not smaller. Can that door be moved away from the corner?

The pillar you don't want in the kitchen unit area could be in the wc instead.

 

If it hasn't been thought of already, the floor joists can be set into the beams instead of on top.

 

Best get your SE input asap then look af these aesthetics. 

But nobody  hardly anybody cares about seeing beams across rooms.

Architects might explain it as respecting the honesty of the structure.

Engineers will say, " you canny change the laws of physics".

 

Looking forward to helping you with this once there are more details.

[George]

You need to get a SE involved to sort out the beam  and columns.

 

It is possible to set steels into masonry - he's right there's is a risk of condensation if the column is very close to the external leaf. However until you know exactly what column is needed it may be a none issue. For example, for many 2-story homes a 152UC is sufficient for the column. These are around 160mm in depth so can be wrapped in 25mm insulation and still be within the inner leaf + cavity. Even with a 203UC you will have a fairly minimal projection into the room which kitchen installers can work around.

 

The temporary works are more complex but if there is a critical reason to have the beam in the wall it can be done. You may also need to more to a box frame rather than a goalpost which will cost more, but aesthetics has costs!

Edited October 25, 2023 by George

[Gus Potter]

7 hours ago, George said:

You need to get a SE involved to sort out the beam  and columns.

You really should start asking questions..

 

There is a massive Elephant in the room here in that you are removing huge amounts of the building that are stopping it blowing sideways, called horizontal stability. Just glancing at your drawings.. you have building stability issues that need put to bed.

 

That little green circle on your drawing could cost you a lot of money.. so ask what it is and the implications.. we are talking thousands here not a few quid.

 

I work with experienced Architect's as an SE  (Architectural designer myself so wear two hats) that understand this concept and communicate this to their Clients early on and how you get around it in a cost effective manner.

 

As the Client push your Architect and SE to work together. Most importantly they should be explaining to you what they are doing, thinking and giving you info to let you make informed decisions.

 

 

Edited October 25, 2023 by Gus Potter

[George]

Hey at least the architect has allowed for a teenie SHS post int he corner!

[Tetrarch]

Thank you for all the replies.

 

The rear is a new build single storey extension 3.5m x 8m with a 6.5m Vistaline slide-and-stack Door that hangs from above and weighs 35kg per sq.m (so 475kg is total) - we'd ideally likely stack this to the right so that is a lot of weight on that outer corner

 

I'm waiting on a few extra drawings and I'll share when they arrive that will show the rear elevation and the new planned roof

 

Regards

 

Tet

 

 

[saveasteading]

52 minutes ago, Tetrarch said:

that is a lot of weight on that outer corner

 

Also a lot of weight at mid span where the beam will deflect.

17 hours ago, Gus Potter said:

As the Client push your Architect and SE to work to together

You seem to have a grasp of the loadings issue  so, yes, do this.

It is all too easy to draw a plan and add notes that the SE has to make it work.

Efficiency, and value, require realistic geometry that the structure can work within. Some architects have been taught  , or absorb, am understanding of structure. Some have not.

 

So get it looked at in principle now, and then the detail can follow.

Make it clear if projecting beams and columns are not acceptable, and that you don't mind paying a lot more for this.

 

 

[Alan Ambrose]

@Gus Potter

 

>>> you are removing huge amounts of the building that are stopping it blowing sideways, called horizontal stability

 

This is because of the big hole for the doors? And the steels won't provide that strength to prevent 'racking'?

[Gus Potter]

On 27/10/2023 at 10:09, Alan Ambrose said:

This is because of the big hole for the doors? And the steels won't provide that strength to prevent 'racking'?

Yes you are spot on.

 

There is not much to go on in terms of the plan you posted.. but it looks like you have big open plan areas on the ground floor at that point thus horizontal stability is a key issue... can dominate the design at times.