problem floor

[gangman]

Looking for some sensible ideas.

The project is a stone built chapel in Wales.
The problem is a suspended wooden floor in a room, that has some rot. The current plan is to take out the floor and replace with a concrete slab. There is a quote for over 20k which is way above the funds available.

So I'm looking for a way to keep a suspended floor but the problem is there is no ventilation.

There is only one exterior wall, over 2ft. thick and it's dressed stone, not a good option for cutting through. Possibilities are 100mm pipes up through the roof, maybe with a fan.
Or maybe vents in the floor of the room.
Any other ideas most welcome.
Cheers

 

[gangman]

If there are no suggestions how about any comments on how effective running pipes up through the roof would be.

The floor area is around 55m2, 10m x 5.5m. Solid floors on three sides.
My thought is to run a pipe, in the void, along the back wall of the room. Then up through the roof at either end. This pipe would obviously have spaced holes in the section below the floor.
To create a crossflow there would be another similar pipe along the front wall.
The architect is not 100% on this idea but it would mean a much cheaper solution as compared to a concrete slab.

Any comments welcome.

 

[freddiemercurystwin]

What made the quote £20K, how deep is the hole at present?

A picture (or a floor plan) as they say speaks a thousand words.

Radon fans systems may be worth investigating as these do essentially the same thing. Convincing the BCO may also be tricky.

 

[gangman]

One of the reasons for the cost is a 2- 3ft void that would need to be filled. Getting 40m3 of fill in there would be a nightmare of a job. Really bad access, no parking etc.

This is the reason for trying to keep the wooden suspended floor, this chapel doesn't have the funds for a £20k bill.

I have got the architect to consider airbricks on the exterior wall and a vent pipe along the back. Though cutting through the stonework wouldn't be a job to look forward to. So pipes front and back would be preferred.

I was hoping someone had come across a similar problem and had maybe used pipes vertically.

 

[tony1851]

Would it really be that difficult to cut 2 or 3 holes through the wall? it's unlikely to be solid - probably decent stone externally, rough stone inside and a rubble core.
i've specified this recently on a stone wall (though only 18" thick, not 24") and once through the outer masonry (which was about 6-7" thick), the rest was fairly easy.

 

[gangman]

This is a pretty sturdy stone wall. Been told that a few years ago a plumber cut through it when fitting a toilet. His words were never to ask him back if they needed any more holes cut through. Took a bit of time apparently.

My time on this job is for free so the quickest option would be the best. If cutting through is what needs to be done then that's what it will have to be. Hopefully venting the way I suggested will be accepted. If venting is not ok then a concrete slab will be going in. Problems are there to be overcome.

 

[tony1851]

Could have been a plumber who just liked things easy!

 

[mfarrow]

Thinking largely outside box here as a non-pro, what about a DPM with a relatively thin concrete slab (i.e. 4" compared with 2-3') on top, then built up timber floor on top of that?

You'd probably have the thickest timber joists in the parish, but it would mean a lot less bulk material.

 

[Alastairreid]

Thinking largely outside box here as a non-pro, what about a DPM with a relatively thin concrete slab (i.e. 4" compared with 2-3') on top, then built up timber floor on top of that?

You'd probably have the thickest timber joists in the parish, but it would mean a lot less bulk material.

Still need sub floor vents though.

 

[gangman]

Would still need air flow that's the problem.

As for filling the void I could do that with slabs of jablite, very quick to get that in.
What I'm looking at is to give them some options, cost being a big factor. They had a quote for 20k off a builder. This was for a concrete slab, hack off and tank walls up to 1m, take out and replace toilet and two stud walls.

My thoughts, pipes are used under a new slab to keep the air flow, so what would change if the pipe ran up vertical. Maybe even one side out through the roof and the other in the loft space to help with pressure differences.

If I can convince the powers that be with a good argument on my method working it would mean a real saving for them.

 

[stuart45]

In the USA they sometimes use conditioning systems instead of ventilation.
http://www.sylvane.com/crawl-space-dehumidifier.html

 

[gangman]

Now we're starting to get some ideas.

 

[tony1851]

Untitled

• tony1851
• 22 Jun 2013
• 1

 

[gangman]

You read my mind Tony

 

[catlad]

Is a block and beam floor not an option.