New suspended floor garage conversion

[Leofric]

herringbone struts?
How many should i fit?

fit them at mid span.
As a matter of interest what is the height of the house floor level above the highest garage floor level ,and what is the vertical dimension from the house floor level to the underside of the garage roof trusses?

 

[ash1212002]

fit them at mid span.
As a matter of interest what is the height of the house floor level above the highest garage floor level ,and what is the vertical dimension from the house floor level to the underside of the garage roof trusses?

So the herringbone struts would they provide more strength and bracing compared to using 8 x 2 noggins?

 

[noseall]

So the herringbone struts would they provide more strength and bracing compared to using 8 x 2 noggins?

We always use solid bridging i.e. 8" x 2" noggs as you suggest. Sometimes plumbers and electricians ruin them though. Make sure they are tight but measure more than one gap and measure away from the centre....or get the first one arrow straight and measure off that. Its so easy to start bowing the joists if you start ramming the noggs in.
Some joists will bow in others will bow out. Get an average going.

 

[noseall]

Staggering the noggs (2" either side of the centre line) helps with the fixing.

 

[ash1212002]

We always use solid bridging i.e. 8" x 2" noggs as you suggest. Sometimes plumbers and electricians ruin them though. Make sure they are tight but measure more than one gap and measure away from the centre....or get the first one arrow straight and measure off that. Its so easy to start bowing the joists if you start ramming the noggs in.
Some joists will bow in others will bow out. Get an average going.

Is it better to stagger the noggins or fit them in a straight row?

Should i fit one set of noggins mid centre or two sets across the floor?

Are the noggins secured with screws or twist nails?

 

[ash1212002]

Staggering the noggs (2" either side of the centre line) helps with the fixing.

You just answered the same time i was responding

Will stagger the joints

Should i fit one set of noggins in the centre or two sets across the floor?

Are the noggins secured with screws or twist nails?

 

[noseall]

Screws or nails.

 

[^woody^]

Struts or noggins are either ivor. But you will struggle to fix steel struts on the bottom of these joists as you can't get underneath!

Bear in mind that there should always be noggins at the ends when using hangers, so you may as well use noggins all over. Dont forget you also need a slim piece between the wall and the first and last joists - many people miss that out and it's very important.

 

[ash1212002]

Struts or noggins are either ivor. But you will struggle to fix steel struts on the bottom of these joists as you can't get underneath!

Bear in mind that there should always be noggins at the ends when using hangers, so you may as well use noggins all over. Dont forget you also need a slim piece between the wall and the first and last joists - many people miss that out and it's very important.

On the first and last joists the ends of the wall I'll be putting some timber or joists there too for added support. I will need to make a notch so i don't block the air vents on the window side

I have two cavity sleeve vents which are just below the void, below the window where the garage door originally was.

There is a distance of approx 300mm where the next joist is, as these are 8x2 joists the bottom of the joists sit just below or under the vents therefore it could be argued there is an obstruction of free flowing ventilation end to end of the floor

Will this be an issue for the BCO?

 

[ash1212002]

Bump, can anyone advise if there should be a clear void/gap to ventilate the floors?

i.e should the joists sit above the cavity sleeve vents?

 

[oldbutnotdead]

Yes, usual minimum is 150mm from underside of joists to oversite.

Not a brilliant plan having the air bricks venting between the joists, they'll not work well when you've filled that gap with insulation.

Somewhere in the approved docs there is a formula for calculating how much ventilation you need per sq m of floor, as long as you hit that number you'll be fine

EDIT Approved Docs Part C page 28.
Openings not less than 1500 sq mm per metre of wall or 500sq mm per sq metre of floor area. Ideal is airbricks on opposing walls to give good crossflow.
At 100 sq mm equalling 1 sq cm the requirement is not onerous, exceeding it will not cause problems