Best way to cut across floorboards in limited space?

[Derek M]

I need to replace the 18mm floorboards in my flat with plywood or OSB sheets, starting with the hall.

Most of the places where I'm cutting the floorboards to lift them it doesn't matter if the cut is straight, but where the new sheets are going to butt up against the floorboards from the adjacent rooms, the cut does need to be straight. As you can see from the attached photo, my attempt to cut a straight line with my multi-tool didn't go very well!

Would this Einhell cordless mini circular saw be a good tool to use for this job? I already have Einhell batteries so that's why I'm considering this one. https://www.amazon.co.uk/Einhell-Cordless-Circular-X-Change-Diameter/dp/B08C7STFVM

I won't be able to cut across the entire width of the hall with that, because the plate will hit the wall at each end, and the handle might get in the way a bit too, but I can just cut in both directions to get as close to the walls as possible. I think the plate will also probably hit the door frame and side wall and prevent me cutting next to them, so even if I can do most of it with the mini circular saw, I'll still have to use something else to cut about 5 inches at the top and 12 inches at the bottom, so what could I use for that and still keep a nice straight line?

I've got some of these old model Evolution rails which I'm not going to use now as I'm going to buy the improved new model kit. Would the Einhell cordless mini circular saw be compatible with them and if so, would it be worth cutting one of them down so I can use it to do these cuts across the hall? https://www.amazon.co.uk/Evolution-Power-Tools-ST2800-Circular/dp/B07HRDG2JG/

 

[Mottie]

Look alright to me - if you're going to put carpet down.

 

[Tigercubrider]

Don’t go too deep. You can set most mini plunge saws to a set depth.

Why do you need to replace ithe boards? Apart from expense, and work, boards are easier when wiring or plumbing

 

[Derek M]

Don’t go too deep. You can set most mini plunge saws to a set depth.

Why do you need to replace ithe boards? Apart from expense, and work, boards are easier when wiring or plumbing

I'm soundproofing the flat and will need to put a layer of self-levelling compound on the concrete slab and then rubber pads which the OSB sheets will sit on. I don't really need to soundproof the hall but it will give me a chance to practice doing these jobs before I tackle the main rooms.

I also need to re-route the water and central heating pipes and wire in new electric circuits for aircon, etc. and it will be a lot easier if I can just lift a couple of sheets of OSB each time the plumber or electrician comes to do those jobs, rather than lifting and relaying a load of cut up floorboards each time. Once that's all sorted, there shouldn't be any need to do any more wiring or plumbing for a long time, and if necessary an access hatch can be cut.

 

[Derek M]

Look alright to me - if you're going to put carpet down.

It's not about the appearance though. The line needs to be straight so the new sheet, which will have a straight edge, fits against the remaining floorboards.

 

[Mottie]

Couldn’t you just mark out a straight line and follow that? Is it the exact same thickness?

 

[freddiemercurystwin]

If you're replacing all of the floor boards then why does it matter if the floor board cuts are wonky? I'm a bit confused as to what the floor make-up will be afterwards? It seems the floor beneath you is concrete slab, then what? Rubber isolation pads with the plywood sitting on top? And the slab needs leveling because the slab is not level but the pads are all the same thickness? Which begs the question what are the existing floor boards sitting on now?

 

[Tigercubrider]

You’d normally use resilient strips or sheets of thin rockwool then lay a floating floor.
Any chance of a diagram of what you have?
I have never run air or pipes in a floating floor

Acoustic RockFloor® - Non combustible Sound Insulation ROCKWOOL

Non-combustible acoustic insulation for floor applications. With high-rise living and buildings with multiple-occupancy becoming increasingly common, acoustic performance of intermediate and separating floors is key in design criteria and specifications. Acoustic RockFloor® delivers robust...

www.rockwool.com

The trick is to not couple the layers. A floor will float on soundproofing but mechanical connections transmit

 

[Derek M]

If you're replacing all of the floor boards then why does it matter if the floor board cuts are wonky? I'm a bit confused as to what the floor make-up will be afterwards? It seems the floor beneath you is concrete slab, then what? Rubber isolation pads with the plywood sitting on top? And the slab needs leveling because the slab is not level but the pads are all the same thickness? Which begs the question what are the existing floor boards sitting on now?

I'm not replacing the floor boards in every room at the same time, so when I lay the OSB sheets in the hall they'll have to fit against the floorboards in the adjacent rooms, and in any event when I do replace the floorboards in each of those rooms, the OSB sheets that I lay in there will have to align with the sheets in the hall, so I need a straight line at those meeting points.

The floorboards are currently sitting on wooden joists. The new floor will be rubber pads on the levelled concrete slab, with two layers of OSB on top to provide the required mass and rigidity. I probably don't need to use ply, as there's no soil and moisture under the floor like there is in a house.

 

[Murdochcat]

I’d be very careful not to cut pipes and cables …..

 

[Derek M]

You’d normally use resilient strips or sheets of thin rockwool then lay a floating floor.
Any chance of a diagram of what you have?
I have never run air or pipes in a floating floor

Acoustic RockFloor® - Non combustible Sound Insulation ROCKWOOL

Non-combustible acoustic insulation for floor applications. With high-rise living and buildings with multiple-occupancy becoming increasingly common, acoustic performance of intermediate and separating floors is key in design criteria and specifications. Acoustic RockFloor® delivers robust...

www.rockwool.com

The trick is to not couple the layers. A floor will float on soundproofing but mechanical connections transmit

I'm just going to use loose rockwool to fill the cavity between the rubber pads under the OSB.

As I say, soundproofing the hall isn't that important and I'm mainly using it to practice before I tackle the main rooms. I might run the electric cables in conduit above the floor in those, and maybe the central heating pipes too, or I might just remove the radiators and get an aircon unit that does heating too.

 

[Derek M]

Couldn’t you just mark out a straight line and follow that? Is it the exact same thickness?

I thought I'd be able to cut a straight line with my multi-tool but it seems harder than I thought to stop it wandering. Yeah, the floorboards are 18mm thick so I need to cut to that depth.

 

[Derek M]

I’d be very careful not to cut pipes and cables …..

Yeah it's OK, I know where they are and none of them are near the top of the joists.

 

[Derek M]

I'm having doubts about whether a mini circular saw would be suitable for this job now, as I read that they're only suitable for doing rip cuts into wood from the edge, not doing plunge cuts like this and it will kickback a lot if I try.

Does anyone make a mini plunge saw? I think a full-sized one would be far too big and unwieldy to use in this space.

 

[big-all]

my bosch 10.8v now called 12v is ideal for this job nail a batton to run against on waste side and run against
can get under cabinets at the plinths at 6" to cut 22mm boards[up to 25mm]
random link but a company i use

Bosch GKS 12V-26 12v Cordless Circular Saw 85mm | Circular Saws

Buy Bosch GKS 12V-26 12v Cordless Circular Saw 85mm and other Bosch Professional Circular Saws at Tooled-Up.com. Fast Delivery.

www.tooled-up.com

you will get attempted kickback all the time this will mostly be when the blade path when plunging is not in an exact path or arc causing odd grip and kick where the blade is fighting and unbalanced in the part cutting/gripping /pushing will constantly be changing whereas careful plunge against a batten both gives support and an accurate plunge path to follow

and by plunging i mean blade exposed to required depth and locked in place but short 0.2 to 0.3mm [about 21.3mm] and touching batton with the nose off the base only plunge cut against batton till blade fully plunged