Minimum wall return size

[c9656750]

Hi

Just building a side extension on my house, its a garage utility, with bedroom above.
The garage will level up to the front line of the house, using a new cavity wall as its left side, and the existing wall of the hiuse as its right side (looking from the street).

Planning has stated that the 2nd floor should be set back approx 300mm, so the 2nd floor wall across the front will be supported off RSJ's spanning between the exising house wall and the new left side cavity wall.

now, i have had to have structural engineer diagrams for the RSJ's etc, and this is fine, the only thing is he has drawn a 900mm wide return wall across the front of garage door opening, leaving me only 2.6m for the new garage door (total width would be 3.5m, so with no return, i could fit a 3.2m door).

Now, i appreciate that this might be minimum width due to the supported RSJ above, but is it, or has the SE just chosen an abitary size?

I cant get hold of him to ask, and the builder is getting close to starting the walls, so needs to know - i guess BC will advise, but i would prefer to amend plans for the bulder before we get that far....

 

[Static]

Wall size can be a factor of load on it, type of block/brickwork, if its supporting lateral forces etc..

Get in contact with the SE if its just load, you could see if a smaller engineering brick pier would be sufficient

 

[^woody^]

Lots of properties have no return to the garage in situations like this, so there would be no technical reason why you can't.

Did you use a proper engineer or just someone to do steel beam calcs, as an engineer should have asked you about what return you wanted.

In any case, you should have sorted this out at the planning stage as if you now change the design, then you will need to see if it is acceptable to the planners - which will delay your builder even more

 

[c9656750]

it was sorted at the planning stage, and the plans show a narrow pillar (IE just the width of the wall), but after that BC asked for calcs for the beams, and the guy who did those took it upon himself to ignore the plands and draw a 900mm return?

the only reason i could think for this was due to build regs...

not sure how any of this could have been sorted at planning stage, as builing regs seem to change according to site conditions???

driving me a bit mad TBH

 

[^woody^]

Ok, it seems like your plan drawer has done one thing for planning, and then when he came to do the b/regs drawing, realised that a return of less than 675mm will require some calcs, and he was perhaps unable to do these, so took the easy option

Your approved planning drawings are what should be built, and it's nothing to do with building regs. Ideally your agent should have considered building regs at the planning stage so that the approved plan can actually be built in terms of building regulations

Anyway, 675mm (3 bricks) external, can be built without needing engineers calcs, otherwise you can have less or no return and an engineer will be able to calculate this no problem - but it will cost you

 

[c9656750]

ok, great, the plans dont actually show how big the return is, but 3 bricks was my estimate from the diagram, - its the SE diagram that shows 900mm - when you say "it can be worked out" - what can? - if the return is smaller, what needs to change to compensate?

ta

 

[freddiemercurystwin]

The engineer will need to do some calcs and if a return as per your approved planning drawings fails maybe insert some steel or similar to beef up the corner to compensate for the lack of masonry.