Qs about chipboard floors, floorboards, tiling, dot n dab plaster board etc

[David Robinson]

I've used google groups to check previous answers to these questions in this group, which has raised some new questions! ...

I've got a wrecked (damp) chipboard floor (in the utility) that I need to replace. I was thinking of laying floorboards to make it easier to take up parts for access later on - sensible or stupid?

Chipboard seems to be preferred these days - why is that?

I want to run new cables down dot and dab walls. If I can feed them down the cavity, I will, but where I can't, is it OK to just cut a trench in the plasterboard? I'm worried that it'll crack when filled. Any tips?

There's a new (expensive) version of the Exakt Saw out, with a 26mm cut...

old 12mm version has been discussed here before. Will this 26mm version be good for cutting (existing) floorboards, chipboard flooring, plasterboard / walls, etc? I use my jigsaw for floorboards at the moment, good old hammer and chisel (sometimes Stanley knife first) for plasterboard / walls, and circular saw for chipboard floors

- but maybe this new tool will be more convenient for all of these jobs? Don't like spend money, but if it's quicker and safer, it might be worth it.

Finally, the floorboards in the bathroom are pretty wrecked. I want to tile over them, and I know with 6-12mm plywood, BAL Fastflex tile adhesive, tiles etc I'll end up raising the floor by about 1". Wouldn't it be easier to just put a new floor down (chipboard?), or would that still need strengthening to hold tiles OK?

Thanks for any help/advice.

Cheers, David.

[The Natural Philosopher]

I have used a series of holes and a coat hanger to drag CAT5. Cant answer for mains.

I have trenched plasterboard now and then. I usually stuff e.g. newspaper in the cavity to support a bonding plaster coat and skim with finish layer.

Id remove everything and go for 19mm waterproof ply and about 6mm of flexible adhesive.

If the floor is flexible, removing allows you to double up joists and herringbone it if necessary.

Herringbone really helps a great deal with decent depth joists.

And whilst it takes time, its bloody simple

[Tim Watts]

Sensible unless you are going to lay vinyl over, in which case you will need to overlay hardboard to prevent the floorboards showing through.

You could lay smaller sheets of ply, well screwed down, say 3 joists square which should be a reasonable compromise.

Because it's cheap and crap? It does interlock, but then that makes it a bastard to lift.

You'll end up going right through the board, so yes, it will probably crack.

You could cut out a wider strip, insert conduit, and repair the strip (see the Wiki), using scrim tape over the joints - but you'll need to feather some jointer filler over somehow.

I'd lift the floor and relay 18mm ply. Or - ignore the 1" - put a ramped threshold in. I have ramps here and it's not particulary obtrustive.

[John Rumm]

Nothing wrong with floorboards... might need to be T&G to satisfy building regs these days - but for retrofit that hardly matters.

Its cheap, and quick to lay large areas. Its also much simpler to get air tight.

As long as the edges can't flap about you should be ok. Probably easier to hide if you scrim over and the PB is also skimmed.

Well given that most of those are at the moment, good old hammer and chisel (sometimes Stanley knife

If spending that sort of money, I would get a multimaster. That's very good for lifting floors and hacking lumps out of plasterboard.

Stick a new floor down. If you use say 19mm WPB ply, then it ought to be firm enough to tile straight onto.

[David Robinson]

It's an existing room, so already skimmed - won't be doing it again, so it's just a case of filling and "hoping" it doesn't crack. Worried about movement where the plasterboard has been cut.

Will it cut neatly too? From the (classic JML) video, it looks like the Exakt will cut tiles neatly.

Cheers, David.

[David Robinson]

That's a great idea - though there's not much room for extra joists, never mind herringbone, because of the number of pipes running through there. Might be able to do something though.

Cheers, David.

[David Robinson]

Damn, yes, vinyl (or lino, or whatever!)

Might as well I suppose - floorboard then ply/mdf seems pointless here.

Oh blimey - you mean repair it like a damaged section (which I suppose it will be!)?

Thanks.

David.

[John Rumm]

SF do metal herringbone that takes up very little space...

[John Rumm]

So back fill with bonding plaster - some will squidge under the free edge of board and support it. Fill just under flush, and then another coat of wither board fill or multifinish to make good. Sand if required.

Yup if you have a steady hand! (or cut against a straight edge). I put a new socket in the kitchen the other day - just marked out the outline of the metal backbox on the tiles, stuck the carbide segment saw on it, and followed the line freehand to cut a neat rectangle through the tiles. Followed up with the SDS to remove the cut out section and brickwork behind. The box slotted in with a nice even margin round the edge.

For lifting floor boards, I normally plunge cut right over a joist (taking care to dodge the nails). If I need to cut where there is no joist at one end, then a plunge cut at 45 degrees at the unsupported edge will let to replace the board such that the free edge is still supported - something I expect would be tricky with an exact saw.

[The Natural Philosopher]

Every little helps.

And you can work herringbone around pipes It doesn't take a huge strain

- even 1x1 works.

Do mark joist centers on the ply before nailing into the plumbing...

[The Natural Philosopher]

Really? THAT is worth filing in the failing memory banks..

[dom]

I've used it, and whilst it's cheap to buy and quick to use, IME it's not the equal of timber (as solid noggins or herringbones), and not so great when you've got non-standard joist spacings.

OTOH because it's so quick and easy, nothing stopping you from adding extra rows beyond building regs requirements.

[John Rumm]

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