venting a floor void through a conc slab.

[Deluks]

Left hand side of house.
Hallway/stairs at the front, kitchen at the back, seperated by a wall. Hallway floor is timber over void, kitchen floor solid.

No airbricks venting the hallway floor, the wall plate and joists ends where the void meets the kitchen floor have signs of wet rot (crumbly, soft) caused by earth and hardcore being backed up against it (aka the kitchen floor)

First job, replace sleeper wallplate and bolt on new joist ends under the dividing wall. Second job, new kitchen floor, dpm, inso, slab.

How to ventilate the floor void through the kitchen floor. Would the use of a tele vent>6"pipe>televent provide a clear path for air to travel?

I know these vents are for directly venting the floor void beneath, but having one at each end of a pipe which runs just under the hardcore/mot (350mm+ under ground) might mean the air has 'too many corners' to go around?
(I'll try and get a picture up later)

 

[noseall]

Provided you are diligent when it comes to sealing the joins (duct tape) and build a robust duct structure then air pressure will take care of the venting.

 

[Deluks]

Cheers, do you know if any connectors are available for joining the rectangular sleeve to a 4" or 6" round pipe?
Duct tape is all well and good but as it will be beneath the slab and the dpm, effectively in the earth. Can't see it lasting out.

 

[theoldun]

Duke, Agree wth what nose says, only one drawback, your more cavalier than diligent, so feel sure that nose won't mind me telling you another way. Google www.allmat.co.uk They do a 225mm x 75mm duct adaptor that fits on to telescopic underfloor duct and trerminates with a 100mm round outlet. Wack length 100mm pipe into outlet under concrete. Put two ducks across. I suppose nose will put picture of duck up now.
old b**gger.

 

[noseall]

Believe it or not i actually used a blow lamp an a couple of pieces of 2" x 2" timber to form a "rectangular" end to a 110mm plastic pipe.

I heated the pipe with the lamp whilst at the same time jamming the two pieces of timber into the end of the pipe and slowly prising (distorting) the plastic into a rectangular shape!

It worked and b.c. loved it!

But as Old Wise-un has stated you can but proprietary fittings.

 

[Deluks]

That's absolutely quacking advice Oldun. Just checked their address and I drive past Allmat several times a week.

Did you write all this out before I posted my last message?


Nose, you tight bugger! (though I have done the same with guttering)

 

[theoldun]

Yes. I also supplement me pension by telling fortunes twice a week.
Hung Fo Sue

 

[Deluks]

The blinding/dpm will be about the same level as the top of the sleeper wall, with this in mind, might I just as well knock out one of these bricks and poke the pipe straight through into the void? Only one televent needed then at the opposite end.

The wallplate, although bedded on bitumen is like a sponge due to the crap that was up against it, as previously mentioned. Will probably remove this section at a time (under each joist end in turn) and replace with cut sections of concy lintel.

View media item 23366

 

[theoldun]

You only need vent and adaptor on external wall. Knock bricks out push pipe through sleeper wall make good brickwork as required. Would put two number ducts in if I was doing it.
Rip floor up, cut back joists, new dpc and plate, bolt extenders on to joists, stand back, admire it.
Hung Fo Sue, Broffer. Sister reply morrow.

 

[Deluks]

Total width of the area about 2.3m. If I can get 2 pipes in I will, although tricky at the other end of the kitchen to find somewhere suitable to put them as there's a door sill in the way for starters.

I'm trying to avoid lifting the floor on the other side of this wall as there's parquet down. I'm gonna try to fix the joists from this side, through the gaps between the joists There's the 4" joist depth plus an extra 2" when I cut out the wallplate (in short sections) so about 6"x 16" hole to reach in and drill sideways.

If I can slide timber through far enough so that it rests on the next sleeper along (doesn't look too far away) then get me arms in and clamp it to existing, then drill bolt holes etc

Might just cut back and butt up the new to the old, if I can find some free or cheap PFC offcuts to join them.

Wierd, but appears to be another timber plate on top of the joists, which the spine wall brickwork is built up from.

 

[theoldun]

If you can only get one in, so be it. I said two, as the more air circulation the better.
If you can get new joist pushed through on to next sleeper wall plate, then couple screw will hold them in place.
If plate on top of joists is sound. then don’t worry. Just make sure it is supported when you cut old Joists out. Seen it before. The ancients had some funny quirks. My grand dad might have built it. I know he done a few abroad in places like Surrey.

By Mai Te Sue, slister to Hung Fo Sue.

 

[mac391]

Why don't you just use timber joists, flooroards and airbricks? The same as the rest of your house..

 

[freddiemercurystwin]

This may (or may not) help, I've not really been following this thread!
//www.diynot.com/forums/viewtopic.php?t=171482

 

[Deluks]

Ta Fred, same problem, same solution.

Mac, too late, ordered in the ballast. I prefer a solid floor under the kitchen though.

Looks like I'll have to place the airbrick above the FFL, and run that telescopic jobbie down through a chiselled out channel on the inside of the wall (solid 9'er) Then pb or tile the wall over the back of the vent.

 

[noseall]

Mac, too late, ordered in the ballast. I prefer a solid floor under the kitchen though.

Wise choice. A solid floor is so much more versatile than a floating timber fella as it is ready to receive any floor covering.

Plus it is far superior, less hassle, stronger, etc etc.