How to route cables

[NotAGolf]

I need to route all sorts of cables around my house. The downstairs floor is concrete, and the roof is very shallow so it's nigh on impossible to get into the corners. This means I'll have to route them at the first floor level.

Last weekend I pulled up the carpet upstairs to evaluate the situation and hit a bit of a stumbling block. There's no floorboards, just huge sheets of plywood. Each sheet is at least 1m wide by 2.5m long, and appear to be fixed down by hundreds of huge staples. They also appear to run under the (stud) walls. Basically I think it's going to be incredibly difficult to get the boards up.

I was wondering if it's perhaps a better idea to attack it from below instead and just take chunks out of the plasterboard ceiling and then get it replaced and re-skimme (or just replace it in it's entirety. We're ripping down the ceiling in the kitchen/diner anyway, so it's only the living room we weren't planning to ruin.

Thoughts?

 

[Samueltastic]

Maybe invest in a feinsaw or a circular saw with a setable depth on it would be your best bet I would say. Watch out for any heating and water pipes though

 

[bitslice]

drill big circular holes at either end of the room with one of those 150mm holesaws

then route the cables under the boards using a rodding cable

if going across the floor timbers, feel around for any obstructions and then chase out notches from above


you can even get special plastic caps to cover the holes
http://wiki.diyfaq.org.uk/index.php?title=Electrical_Installation
but I seem to recall these were quite expensive.

although gluing the circular blank back in the hole is possible with a bit of support

 

[BigBoy]

Easier and cleaner to pull up boards or cut them in place than damage a ceiling you dont intend to plaster.

Ply flooring is fairly common in America more likely to be chipboard un the UK, whats your location?

 

[mad_allan]

No option of taking them on the outside, depending on what cables you are running of course?

 

[Bickaxe]

Maybe invest in a feinsaw or a circular saw with a setable depth on it would be your best bet I would say. Watch out for any heating and water pipes though

I did this. It was chipboard but I set the circular saw to 25mm and ran a line straight down the middle and the supporting joist. No marks on the joist when I lifted the boards and we ran our heating pipes all the way.

Screwed back down afterwards.

 

[NotAGolf]

drill big circular holes at either end of the room with one of those 150mm holesaws then route the cables under the boards using a rodding cable

I think there's too many obstructions for this to work. There's a small hatch in a couple of places and it's full of off cuts of wood and other rubbish. And unless the holes are massive I wouldn't be able to see what I was doing to avoid them.

Ply flooring is fairly common in America more likely to be chipboard un the UK, whats your location?

I'm in the UK. It's definitely not chipboard as I can see the layers glued together.

No option of taking them on the outside, depending on what cables you are running of course?

No there's too many cables for this approach. Plus a lot of the cables need to run from the centre of the house.

I did this. It was chipboard but I set the circular saw to 25mm and ran a line straight down the middle and the supporting joist. No marks on the joist when I lifted the boards and we ran our heating pipes all the way.

Screwed back down afterwards.

I didn’t realise you could get circular saw’s with adjustable depths. :/

A few problems with this approach:
- The staples holding it down currently are obviously stapled into the joist, so I’d have to saw through both wood and the staples (then somehow pull it up with a crowbar). Don’t you normally have blades that cut wood or metal, not both?

- The joists are only ~2 inches wide, so if I cut the current boards down the centre of the joist, then screw them back down, they’re only secured by an inch of joist either side. Will this be strong enough? I guess it’s not that different to how they are currently… Joist’s are approximately 40cm apart.

- I won’t be able to get to some joists right at the edge of the room as the saw itself is too wide. In that case I thought I could cut as close to the joist as possible, then fix some wood to the underside and screw into that (see wonderful diagram below). Would this be strong enough? For a small section I imagine it’s ok, but if it had to run the entire length of a wall I doubt it’s strong enough

 

[BigBoy]

My joists are only 2inches thick, the house is 80+ years old and still has the original floor, I'm sure it would be fine.

Remember you don't want to be cutting the boards along the entire length of a joist that cut should be short, the longer cut should be 90o to the joist. So load is spread over more than one joist.

You only need to take up a few small sections of floor equal to taking up one floorboard every 6 so you can thread the cables along the cavity and through joists, also don't notch make sure you cut a hole in the joist as it will remain stronger than way.

 

[Bickaxe]

When you secure the floor back down, the supporting block should be attached to the joist to strengthen the floor. The diagram you have would probably result in the floor bending over the join when weight is applied.

You should be able to feed the cables through the gap under the floor so you won't need to take out large sections