Wall plate for suspended floor

[Jaxta1]

Hi,

I have a couple of questions about how to fit a wall plate to hang a suspended floor in new extension.

I would be attaching it to the current exterior gable like the below pic.

Would there need to be a damp proof membrane between the wall plate and the wall?

Do the hangers get attached before the plate it attached to the wall?

Should I scrape of the render on the wall before attaching it?

Many thanks

Untitled

• Jaxta1
• 9 Nov 2014
• 2

 

[ree]

Knock off the render to 50mm min. above the plate.

Run DPC behind the plate.

You could mark the hanger centres, and then bolt-on the plate - with the bolts centred in the joist bays (as in the pic). Use a piece of the sheet sub-floor material to pick up your actual hanger/joist centres, and fix the hangers to suit.

AAMOI: before fixing the plate, it would pay you to bring the interior room FFL to the gable and level it across - then, knowing your sub-floor, and finished floor materials thickness, you would know exactly what you are working to.

 

[Jaxta1]

Thankyou for help.

How would you mark exactly inner floor level on the outside gable?

There's no door on that wall, so I thought I'd have to mark a line around house from a door using a spirit level? Can't imagine that would be 100% accurate though?! I'd be knocking through the wall/inserting an rsj once the extension had been built

Is it a problem if the plate on current external wall is below the current house dpc? Not that I know exactly where this is as it's rendered to the ground.

Sorry what did you mean by using sheet sub material to pick up the hangers?

 

[ree]

At the proposed new knock-thro opening position, drill a hole (using say a 6mm x 300mm tipped bit) from inside to outside the gable wall and pick up finished floor measurements from that hole.

You have to determine where the DPC is in the gable wall - knock off a little render to expose it. But only when you have transferred the the interior FFL can you be certain of what is going where, and how things might affect each other.
Its doubtful that the DPC will come above the plate but, first, investigate.

Ignore that part of my post - simply set your hangers on 400mm centres.

 

[Jaxta1]

I'm finding imagining where the dpc is quite confusing so I'll need to find out as you say - I'll try what you suggest, just worried if I drill squint it will throw me out!

You might just be able to see on the below pic the house is built on a slope. I think the FFL is just above the air vents on outer wall.

Either the current DPC at the higher ground level end is below the ground level, or it's above the suspended floor level. Neither seems right, but if it's the latter then the new wall plate would be below the existing dpc.

Could moisture even get to the wall plate as it would now essentially be on an internal wall, the ground would have a membrane over it, and the wall plate would have a dpc behind it?!!

Untitled

• Jaxta1
• 9 Nov 2014
• 2