Suspended timber floor repair

[oldbutnotdead]

Evening all,

Been doing a little bit of floor investigation- the pics are not really worrying me much! I did chuckle at the alleged concrete oversite though- it appears to be tarmac. Shame it is too near the joists and no DPM under it but hey......annoyingly the woodwork looks relatively modern, but none of it was treated or stamped so I may be wrong. Doesn't look 150 years old though.......

First look under the floor

• oldbutnotdead
• 19 Jan 2014
• 1

Far more worm sign than I wanted to see- I was expecting the damp though.

The shoddy corner

• oldbutnotdead
• 19 Jan 2014
• 1

There;s a downpipe on the outside of this wall. Hopper head was blocked so potentially 10 years...

Current situation- joists are 2" x 5" on 4 sleeper walls (not tied to the room walls at all). Total span is 3750 (yes sorry for mixing units), 2 sleeper walls are about 100 from the joist ends, the other 2 are about 1300 from joist ends. Calling them walls is a bit excessive- they're bricks wodged into the tarmac with a lump of stick on top. Said stick has not rotted or suffered worm (except in one very damp corner) unlike the floorboards and the joists.........

So they're all on the bonfire pile now. Questions for the massive (after a good read of Part C) are;

Do I have to use joist hangars on the ends of the joists? I'd rather not, mainly because the brickwork is deeply shoddy so getting any sort of level is going to involve a lot of packing and notching (the nearest bed to level meanders by about 40mm around the room). Given I'll be using 45 x 95 I'll stick noggins in to give the thing some stability.....

The room is a slightly comedy shape. See drawing (if I can make it work)

Plan

• oldbutnotdead
• 19 Jan 2014
• 1

OK, the joists currently run top to bottom (and I'm planning to repeat that with the new joists).What's going to be the best way to deal with that silly diagonal wall bottom right? My current thinking- a joist parallel with that silly wall and blocked off it by 45mm and screwed to the wall. 2 'normal' joists will intersect- cut those joist ends to correct angle, spike them and support each joint with a brick or 2 with some polythene on top.

Cheers

 

[conny]

Have you considered removing the suspended floor and having it in-filled with concrete?

May need to be dug out a bit as from the pics it doesn't look as though you have much room below at the moment.

 

[oldbutnotdead]

Have you considered removing the suspended floor and having it in-filled with concrete?

May need to be dug out a bit as from the pics it doesn't look as though you have much room below at the moment.

Yes I have. I have a personal loathing for concrete floors in houses- not quite sure why, maybe dates from a childhood living in a farmhouse with cold stone floors. Or maybe its that I'd need to preplan all the service routes instead of just chucking it all in as I work out what I need/want

Plus if I fill this one in I'll have to fill in the hallway and the front room as well (underfloor ventilation issues). I'm not dismissing concrete out of hand, just I'd prefer traditional timber if I can get away with it.

Talking of digging out, I'm having to go down another 100mm anyway to give 150 airgap under the joists- the French drain outside is going to have to be at least 300 deep to be below the oversite. Boo. Think the foundations stop at 250.....

 

[tony1851]

As per Conny, long-term you would save yourself a lot of hassle by having a solid concrete floor. With 4" insulation underneath, it will be warmer than a timber floor, and no damp-problems.
You can put plastic ducts under the concrete piped to your existing underfloor void so that ventilationn is maintained.

 

[catlad]

If you are going to pack some of the joist with bricks then you could use bits of slate as a dpc.

 

[oldbutnotdead]

As per Conny, long-term you would save yourself a lot of hassle by having a solid concrete floor. With 4" insulation underneath, it will be warmer than a timber floor, and no damp-problems.
You can put plastic ducts under the concrete piped to your existing underfloor void so that ventilationn is maintained.

Yerse, concrete is tempting. I'm planning on insulation between the joists anyway (stawberry net and 100mm roof insulation at £1.20/sq metre instead of solid 100mm at about £10/sq metre.) And point taken on the ducting- I'm contemplating some of that for the dodgy corners even with suspended floor (though shouldn't need it once I get proper clearance under the joists)

I think my real dislike of concrete is that it is a very permanent decision- once it goes in it is staying there til the house falls down. And I'd quite like the option of being able to get at the base of the walls so if I make the wrong call on sorting out the rising damp/condensation I can do something about it.

 

[oldbutnotdead]

If you are going to pack some of the joist with bricks then you could use bits of slate as a dpc.

Always a good standby, slate! I'm actually planning on copying the existing design- honeycomb sleeper walls on top of the oversite, polythene on top of the wall (it'll be wide spaced bricks really), 3 x 1 all the way across each sleeper wall, joists sitting on 3 x 1 and spiked to it to stop them wobbling while I'm putting noggins in.