Suspended timber floor opinions...

[Munzy]

I am planning on putting a suspended timber floor over the old brick/stone floor of our garage as part of the conversion to annexed accommodation. The voids between joists will be insulated and I'll likely chipboard on top and then lay carpet in the bedroom and engineered wood planks elsewhere.

The garage is single story, measures 6m x 4.4m (internal) and has a brick cavity wall all around.

I've considered two options but am keen to get opinions on whether they meet building regs and which you would choose.

Option 1: Build a 6m sleeper down each of the long exterior walls and a 6m sleeper down the middle of the garage. Run 120x47 joists the full 4.4m width at 400 centres.

Option 2: Run 220x47 joists the full 4.4m width and secure them to the exterior walls with joist hangers.

I believe both options are suitable for the span taking into account the central sleeper support for the smaller joists in Option 1 versus the lack of central support but larger joists in Option 2. Option 1 is cheaper due to smaller joist size and will give a little more height to the finished rooms.

Do both meet regs? What would you do?

Thanks!

 

[trevorbayliss]

I am just doing a suspended timber floor on my extension.

You need a 150mm breathing space below the bottom of the joist.

Another option is to fix a joist flat to the wall and bolt it or resin anchor it to the wall all the way down for 6m (both sides). You then fix joist hangers onto these wall plates and run joists off it. It may be easier then building new walls.

My sleeper wall in the middle of my main room had to have a 450mm wide foundation and it was 300mm deep. This is what BC said i needed here.

Your span of 2.2m with a sleeper wall and 120 joist works as does the bigger joist with no sleeper wall. I would go for a sleeper wall and a deeper joist just so you get a really solid floor. My span is also 4.4m, but i am using a 145 x 47 joist and sleeper. The cost was hardly any different between the smaller joist. Your ventilation space may dictate the size the the joist though, so you may have to go down to a 97mm joist and 2 sleeper walls.

 

[Munzy]

That's some great insight, thanks!