New Mezzanine Floor

[xvivix]

Looking for some advice on a supporting wall for a mezzanine floor.

Im looking to build a mezzanine in a pop-up office conversion. There are 2 spans one 4.8 meters and one about 3.5. I am planing on copying the plan from a neighbour, but am unsure about his supporting wall. The plan is to have ledger boards bolted in to the brick on either side of the span with a timber stud wall in the middle. Were using 2x8's for the joists.

The brick is sound so not worried bout that, just wondering if anyone has any suggestions for the load bering stud wall. The neighbour just has a ledger bolted into a stud wall. Is this sound?

please see the attached image for clarification. (thats the neighbours)

Thanks for any advice.

 

[JohnD]

I had premises like that, but the roof had a lot more timber and ironwork holding it up. Has yours been cut away?

If it was me I would want a SE to look at it.

 

[ree]

I can see a typically well constructed roof - a roof of its period.

There is a massive truss - there will be others spaced for the loads.

One large purlin is visible so presumably the other is concealed by wrappings. Or a timber rafter arrangement is framing that roof section.

The thin, lightweight glazing bars carry a glass roof.

I'm curious as to where the missing timber and ironwork would fit in?

 

[JohnD]

mine was equally massive and had Y-shaped timber pieces in the middle with iron rods. It is fully slated, no glass. Steeper pitch, I think.

I might get a picture next time I'm passing.

 

[ree]

My question does not concern your past building but the building in the pic? What suggests to you that the"timber and ironwork" "holding it up" "has been cut away" from the structure in the pic?

OP,

if the neighbours framing has been passed by BCO then you should have no trouble getting your copy cat framing passed also.

 

[cAtLeYx]

Construct your centre span supporting wall in blockwork.? There are a few on here who could advise on stud work dimensions & centres if a timber stud wall is required.

 

[tony1851]

I think studwork would do fine here, though best clad in OSB for stiffness. Depending on the loading,
you would be best getting the studs designed with regard to size and spacing. It would be better to sit the joists on top of the stud wall, rather than on a ledger. Would the concrete floor be sufficient to support the load from the studwork?

 

[RonnyRaygun]

To comply with regs and span 4.8m with office loadings you really need to put your 50x200s in at 225 crs max - and that's assuming C24 timber. There's no problem using ledger boards and hangers on each side of the stud wall - as long as the ledger boards are bolted securely enough to the stud wall.

 

[RonnyRaygun]

I think studwork would do fine here, though best clad in OSB for stiffness. Depending on the loading,
you would be best getting the studs designed with regard to size and spacing. It would be better to sit the joists on top of the stud wall, rather than on a ledger. Would the concrete floor be sufficient to support the load from the studwork?

Also, if sitting your joists on top of the stud wall you either need the studs directly under the joists or you need to have the top plate designed to span between the studs with a joist bearing onto it. 50x100s would be ample as studs though.

 

[ree]

As tony1851said: "studwork would do fine" yes, of course it would.

This is just an everyday case of framing studding set out at 400mm centres, with 100mm x 100mm posts below all pressure points eg where the joists cross the top plates.

Given that engineered joisting to span from one outer wall to the other would work best (not sawn lumber) - web squeeze blocks would pick up any upper flooring loads on the flanges.

There's no need for complicating it - a call to the Eng. joist Mfr would indicate the joist section needed.

 

[RonnyRaygun]

This is just an everyday case of framing studding set out at 400mm centres, with 100mm x 100mm posts below all pressure points eg where the joists cross the top plates.

Given that engineered joisting to span from one outer wall to the other would work best (not sawn lumber) - web squeeze blocks would pick up any upper flooring loads on the flanges.

100x100 posts would be massive overkill for a simple office floor.

It sounded to me like they may already have their joists which is why I gave them a spacing for 8x2s.

I'm sure engineered joists at 8.3m long would be more expensive than sawn timber.

 

[ree]

Agreed: 4" x 4"s would be overkill. i was rushing, and visualising about pressure points in storied framed houses.

Surprising news about the price comparisons - most framing crews have the eng joists lifted in as one length pieces - no crossing, so there's a massive saving on time/price. No shrinkage either - the curse of modern sawn lumber. Shrinkage can be 3/4" to 1-1/4" for a two story platform framed.

 

[tony1851]

Would shrinkage in this case be a problem? - they just want it for storage.

 

[ree]

There would be some shrinkage esp in any sawn lumber, and the plates - similar to whats sometimes seen in loft conversions.

My last para above was merely a bit of general information.

However, if it was my job i would, in spite of extra costs, do it with engineered joists simply because of more control, and less chance of a call back.

 

[RonnyRaygun]

Would shrinkage in this case be a problem? - they just want it for storage.

Where does it say it's just for storage?