Whats underneath my carpet?

[mh22]

Hey Guys,

I have just redone our bedroom, throwing out the carpet and laying a laminate floor.
The floor underneath the carpet was the same I encountered a few months ago when I was tiling the bathroom floor (which was also carpeted - yuk!).
First, I was wondering what floor it is. They are large, faintly greennish slabs. They are all nailed ( I guess directly onto the joists beneath?) and
individually slabs are glued next to each other to build one smooth surface. There was lots of writing on them "this side up" and "peaces should be glued" and plenty of number but not the name.
The floor in the bedroom was squeaking quite a bit, in particular where the panels meet, so I was trying to get clever and tried to drill a few screws next to the nails down just to give up after a couple minutes trying - its was impossible to get the screw more than an inch in, it was sqeaking like crazy and eventually just locked the scew.
I didnt have any nails nor did I have an idea how long they need to be, so I gave up.


I need to know what sort of board this is. the reason is that I had a massive, hidden leak in my onsuite (which happens to have also the same subfloor) and all the floor was wet over a long period of time. Im about to rip everything out to assess if there is serious damage and if there is, what to replace it with.

Can anyone give me a pointer as to what this subfloor could be?
Btw, the house is a bit over 10 years old, so its fairly new.


Thanks in advance
mh22

 

[JohnD]

it is probably chipboard, which is an awful material. the green colour indicates that it is (supposedly) moisture-resistant.

pull it all up and put down ply.

btw it sounds like you might not have pilot-drilled for your screws adequately.

 

[mh22]

Hey John, thanks for your quick reply.
How can I be certain its chipboard? I was thinking I shouldnt have a problem to put a screw into chipboard? Didnt expect it to be that tough
I just wanna be sure and not rip somethign out unneccessarily.

Either way, I feel I will have to lift the boards in the onsuite, they have been soaked too much in my opinion. Problem is, some boards overlap into the bedroom so I have
to cut them guess. I dont quite know where to start lifting them as they are all neatly glued togethter. Maybe I should just cut them open where there are no nails? (and therefore no joists).

Also what thickness of ply would you suggest for a floor? Also is it suitable for under a shower cubicle?

Im quite good with DIY but sub-flooring is a new one for me and makes me a little nervious, so any pointers are appreciated (or a link to a good guide if you want a shortcut )

Thanks in advance!

 

[JohnD]

it IS

18mm WBP ply is great for flooring, it is stronger than chipboard, lasts longer, and the WBP grade is made with waterproof glue.

To take up the old stuff, use a circular saw with a TCT blade. That will not be blunted, and if you accidentally go through the odd nail it will cut through it.

Usually cut through the centre-point of a joist. If you cut on your side of a joist, the old board will still be supported but you will have to screw a bearer to the side of the joist for your new board to stand on. You will also have to do this if one of the joists runs under a wall. Put trimmers or noggins under any unsupported short edges. Do any underfloor wiring or plumbing work while it is open, making traps or hatches if useful, and fill any gaps in the mortar especially of external walls. you can fill round joist ends with expanding foam and it will prevent draughts.

As lot of the old nails will not come out, I find it easiest to cut old chipboard into quite small pieces so you can lever then out and then deal with remaining nails. Don't kneel on them.

Try not to fall through the ceiling below.

When deciding where to cut, lay our a sample or two of your new boarding, so it will fit with the least cutting, and cut a very straight line.

You can pack fibreglass insulation under the floor, it will deaden sound as well as giving heat insulation if there is a cold space below. The heavier batts are better for sound but more expensive than loft rolls. Don't put it under the bathroom in case of water leaks.

Here's one I did earlier

View media item 4494

 

[mh22]

Hey John, thanks for your information and pictures.

After looking arround in the on-suite, I definately will be replacing the floor boards. Not only because of the water leak we had but also because I want to put in a low-profile shower, where the tray sits more or less flush with the rest of the tiled floor. For that I need a low-profile waste which needs to go underneath the floorboards due to the lack of space underneath the shower tray.
So while I have to do that, its probably not that much more work to put in new floorboards as well and leave an opening for the waste.

A few, finishing question if you dont mind:
- 18mm ply is fine but I dont know how thick the current boards are. Is 18mm standard? Im just worried I may end up with an ugly height difference between
bedroom floor and new on-suite floor.
- Would you suggest screwing or ring-shank nailing the boards? I would opt for screwing coz the boards in the rest of the house are quite squeaky in high-travel areas. As far as
I understand, screws will prevent this from happening. Will brass wood screws do?
- Would you suggest plain plywood boards or tongue/groove? Would either need glueing?
- You suggested WBP Plywood but I read they are not for structural work and 18mm "Structural Spruce Plywood" (Wickes) should be used instead (for flooring). Whats your thought
on that?

I think with those questions out of the way I can start the floor replacement at least ... and then move over to the bathroom forum section

Thanks in advance!
mh

 

[JohnD]

18mm is usual.

I prefer screws. You can tighten them a bit more if anything squeaks, and you can also take them up if necessary. Drill pilot holes first and countersink them slightly.

Brass screws are too soft and weak.

The advantage of plain boards, well-nogged, is that you can take them up more easily. In a bathroom you may sometimes need to do that urgently. T&G does however hold un-nogged joints a bit better, especially if screwed. Some people thing this is a satisfactory way of making an un-nogged floor. It isn't, although it will usually last long enough for you to sell the house.

I have used the structural spruce, and it is a lot rougher than the WBP I have also use (which is good enough to stain and varnish, but that's another story). The spruce is graded for building, and the better ply isn't. I don't know if the better ply is in some way inferior, or if it's just that it isn't usually used for flooring.

 

[HH1]

Chipboard could also be 22mm.
22mm on ground floors, 18mm on floors above.