Is a double skin wall is acceptable for this scenario?

[cleggy0204]

Untitled

• cleggy0204
• 19 Sep 2012
• 1

Hi Guys,

Looking for abit of help/re-assurance.. I have a commercial building to which im looking at putting in a mezzanine floor to accomodate more offices to the upstairs.

Ive had various discussions, regarding what would be the best way to go about this, and the most substantial one being this one:

I have attached a picture (Shocking use of paint - I know!) The top black line is the existing single skin wall to which the current mezzanie is supported from. We plan to construct a wall at 90 degrees to this - (Hightlighted in red!) The proposed wall is 6.5m long and 3m high, to match the existing floor level, this wall is to be double skin 4inch concrete block, with no apertures. The right hand side of this skin to to have a small return.

The original design has no allowances for any pillars, although these could be added without any deficit to use on the below space.

The joists then sitting in this wall are 6m to either side (appreciate that the drawing makes it look off centre) - 12m span in total.

From obviously knowledge this just seems a standard construction, but with the wall supporting such a load (?) is there any alteration that need to be made?

Appreciate any help.. and thanks in advance

 

[cleggy0204]

Can anyone offer any guidance with this?

 

[freddiemercurystwin]

Getting Building Regs for this little lot?

 

[cleggy0204]

No option but to consult LABC

Just wanted to see if the concept itself is possible?

 

[^woody^]

Check out the nearest block of high rise flats.

Note the wall at the bottom

 

[cleggy0204]

Cheers Woody!

I had convinced myself that its just similar to a convential new build, but 600mm higher .

Was just worried about the weight in the floor with there being 6m span either side.

 

[freddiemercurystwin]

Why is it a double skinned wall? In anycase the joists would need to be massive to span 6m. The standard span tables don't even go that high, the maximum span you can get using the span tables is a 75X220 at 400 centres is 5.4m so you're gonna have to think again about getting the spans down or maybe introducing the odd steel here or there. Your wall would need a foundation but adding a steel here or there may mean a continuous wall would not be required. Prob gonna need an SE.

I don't really understand what's there at present tbh.

 

[cleggy0204]

http://www.oakworthtimberengineering.co.uk/I-joist-I-beam.html

Was specifing i beams - 6m doesnt seem a problem to get hold of! (fair enough there are extra charges for them being non stock, no doubt!)

Its a concrete slab in a unit.

Double skinned for support, and allowing more joist length to spread over both skins and the cavity.

Binned the idea of a single skin, 2 seconds after thinking about it ?

 

[freddiemercurystwin]

Sorry, I sent my crystal ball away to be repaired, you seem to have all the answers anyway.

 

[cleggy0204]

Super, just wanting some info gleening, but i think woody had it sumed up.

With regards to internal alterations, is it neccesary to apply for a building notice/warrant to carry out this? Obviously aware that its structural, however its not altering any structure? ( existing apertures being made wider etc? )

Understand that building regs need to be following in terms of the above with structure and fire egress, but is it a requirement to get the notice?

Ta,

 

[^woody^]

You are probably affecting means of escape and fire spread, as well as the structural wall and foundation and floor.

You can't use a building notice for work to a commercial building