extension 1st floor joist fixing

[gismo]

hi all,

i'm nearing the first floor stage with my extension, and i am wondering how is best to attach the 200mm floor joists to the existing house wall. i've searched the forum, i think i've found two main methods and i'm unsure which is best.


1 - attach a lenght of 50 x 200 along the existing wall and attach the hangers to this

2 - use heavy duty hangers directly attached to the wall

Are these the best/easiest methods? if so which one do you guy's recommend.

(i think that option 1 sounds easier to level but i'm unsure how to attach the 50 x 200 beam, coach bolts and plugs or resin)

any help appreciated - thanks in advance

 

[^woody^]

Knock holes out and build the joist in if possible

Use hangers if you can fix them level relatively easily.

Your option one is the easiest if you may have problems in getting a level line, otherwise one of the other options. Just use m12 or m10 expansive bolts every 5-600mm. No need for resin, and best to stagger them at 1/3 from the top and bottom for alternate bolts rather than along the centre of the timber

 

[gismo]

thanks for quick reply woody,

do you mean fit the hangers in the wall or the actual joist itself?

 

[joinerjohn]

Last extension I worked on, I gave the builder a level for the inner blockwork to be. When it was up to this level, I cut and put the joists in , spanning from one wall to the other. Spaced them out correctly and fixed in position with timbers running across the joists on top.
The builder then continued upwards with inner and outer leaf, encasing the joists with the blockwork.
Came back after roof timbers were on and tiled to put flooring down and internal studwork up.

 

[^woody^]

thanks for quick reply woody,

do you mean fit the hangers in the wall or the actual joist itself?

Either

Knock out holes for the joists - only practical if the joist level is the same as an existing course - and the course is level

Or fit hangers - a few drill holes and these will knock in. Again it depends on how level you can get these

 

[geraint]

bolt a timber to the wall and use jiffy hangers...

so much easier to fit and to get your levels...

before you either rag bolt or chemically fix, just screw the timber to the wall... once level, drill all your structural fixings.

no timber movement with the bigger drill bit...

 

[gismo]

thanks for the suggestions, i think i will use a timber and jiffy hangers as i imagine it will make levelling up easier.

 

[theoldun]

Without wishing to contradict any of above posts, may we make a couple of further suggestions.
Use STANDARD timber to timber 225mm long joist hangers in preference to jiffy. Couple of coppers more, but much better.
Nail every hole with sheradised 30x3.7 square twisted nails.
If you screw plate to wall before bolting, then use Through Bolts. Do not use raw bolts rag bolts, shield bolts, call them what you like, as these all need a bigger diameter hole in brickwork than your fixing hole in timber plate. Through bolts, the anchor is same size as bolt. Rattle drill straight through timber and brickwork in one hit, push bolt in and tighten.
oldun

 

[geraint]

Without wishing to contradict any of above posts, may we make a couple of further suggestions.
Use STANDARD timber to timber 225mm long joist hangers in preference to jiffy. Couple of coppers more, but much better.
Nail every hole with sheradised 30x3.7 square twisted nails.
If you screw plate to wall before bolting, then use Through Bolts. Do not use raw bolts rag bolts, shield bolts, call them what you like, as these all need a bigger diameter hole in brickwork than your fixing hole in timber plate. Through bolts, the anchor is same size as bolt. Rattle drill straight through timber and brickwork in one hit, push bolt in and tighten.
oldun

as i always chemically anchor i never thought of that....

cheers

 

[gismo]

thanks for all the suggestions guys, i've put them in now, i ended up cutting them joists into the block work.

just one more question now though -

is it ok to fill the gap in between the brickwork and joist with expanding foam?

 

[gismo]

thanks for all the suggestions guys, i've put them in now, i ended up cutting them joists into the block work.

just one more question now though -

is it ok to fill the gap in between the brickwork and joist with expanding foam?

 

[landyandy]

Foam is a bit of a bodge.

Use slate jammed nice and tight and a bit of mortar.

Andy.