Underfloor project, ventilation and insulation

[Al1234]

So I am nearing completion of a project that has been on the go for the last couple of months. I got some good advice from the site and the following threads and so thought I'd come back and post the results:

//www.diynot.com/diy/threads/underfloor-insulation.470881/

//www.diynot.com/diy/threads/subfloor-ventilation.463584/

The work started last November and was slow at first as getting into, and out of the lowest parts of the subfloor was hard work.

So what have I done, removed a large amount of builders rubble, particularly around the fireplace. This was necessary mainly to enable me to get in and out of this area. I also removed the remnants of the previous central heating installation, and at least two previous electrical installation - one from the 30's and one from the 60's.

I then installed 100mm Knauf EkoRoll in between the joists pinning it up with lengths of polypropylene strapping and staples. At the same time I replaced all the pipe lagging, that which was in place has been on for about 20 years and in some places at melted!

Also I sought to increase the underfloor ventilation by adding two new air bricks to one side of the house that previously had none as well at the door to the underfloor storage area which had not external ventilation. In the early stages of the job water would bead up and run down the wall, this has already been stopped during the course of the work. Some further monitoring of the ventilation will be required throughout the rest of the subfloor.

 

[Jadele]

Looks a nice job mate - good work!

I can imagine what a horrible job it must have been

 

[Al1234]

Thanks, it was pretty grim in places, especially in the section beyond the sleeper wall in that picture! The biggest problem was getting the section of insulation in without getting it covered in dust. I found the best way was to cut the section to length in a more spacious section and then roll it very tightly and bail it using the strapping. It still picked up loads of dust as you tried to unroll it and then push it up between the joists but I think it helped.

Some sections were easier to work on, this was under the front of the house where there was more space. These went in really easily and then I could fix it all up with one long length of strapping. Also shows one of the new ait bricks put into that side of the house.

 

[Ian H]

Nicely done

What did you do for a work light, head torch?

 

[Al1234]

Nicely done

What did you do for a work light, head torch?

All with a head torch, I enjoy caving as a pastime and am quite comfortable working in small spaces!

 

[Al1234]

Here is the selection of scrap pulled out of various parts. Mainly just to make it easier to access between the joists to put the insulation in place. Also cleared out several big flexible buckets or rubble, most of which had to be pulled back from the low sections by hand a few pieces at a time.

Generally it's much easier to move around the bits I need to get to.

The worst part of the whole was rectifying the poor junction added to the ring final circuit to power the burglar alarm. They obviously just lifted the floor in the utility room (before they tiled it) grabbed the gable and spliced into it. Leaving the JB free floating and the cable hanging dangerously close to a CH pipe. Having got to it, being in the lowest section of the floor I was able to re position the JB, having cut through the spliced section and moved underneath and away from the CH pipe. It is now fixed to a joist and the cables clipped at either side. At some point I may go back and refit with a maintenance free box as I just reused the one that was in - it is accessible at least!

 

[Al1234]

Plan of the new ventilation layout. Added two air bricks but also created vents through the three doors, one external and two internal. I think I may have to go back and punch some holes in the solid walls that run north/south to get a good flow of air between the new airbricks and the originals.

 

[Gossamer]

Nice job. Regret not insulating my lounge floor before sanding it etc although my dining room is yet to be done so I might do that.

I've seen this done with a membrane put in between the insulation and floorboards, did you do this or is it insulation below boards? I think its a vapour membrane.