Conduit through wood board insulated wall

[James34347]

I’m installing 60mm wood fibre board insulation on internal side of the walls of my terraced property.

I’m thinking of getting a fibre internet connection installed at some point.

Bit concerned about some workman turning up with a massive drill and making a mess of all the plasterwork and boards trying to feed a cable through.

To try mitigate this I was thinking about fitting some 20mm PVC conduit though the wall, filling it with insulation, and putting blanking caps on either end. Then when I need any cables though the wall I can feed them through this.

Don’t see any reason it would be a bad idea, but wondering if anyone has done similar.

Thanks

 

[paulc]

For data cable, 20mm conduit is an overkill. I used some 12mm conduit here - Made the mistake of using some corrugated stuff which proved to be a major **** to feed cables through. If I were to do it again, I'd still go for 12mm, but make sure it has a smooth bore.

 

[a twig]

What @paulc said - it’s a very sensible idea, and his approach is sound. If you want to be really overkill you can make a bigger hole and use an insulating sleeve around the 12mm pipe to reduce the effects of the thermal bridging across all the layers of the building fabric

When I wanged in a 150mm hole for an air conditioning outlet through a cavity wall I didn’t really think about the thermal aspects and now we have a cold spot around the vent internally that very happily collects condensation around it during the winter. Obviously a 12mm pipe will have a much smaller impact than a 150mm one though so up to you

 

[Flyfisher]

For data cable, 20mm conduit is an overkill. I used some 12mm conduit here - Made the mistake of using some corrugated stuff which proved to be a major **** to feed cables through. If I were to do it again, I'd still go for 12mm, but make sure it has a smooth bore.

As a mild digression, a smooth bore is definitely preferred but I've also used 10/12mm corrugated conduit (in a vehicle) where its easy-curving is an advantage, though you're right that it makes feeding cables more difficult. To overcome this, I use a thin string and tie a small piece of rag or kitchen paper at one end just large enough to easily fit within the conduit but not be tight. Then use a vacuum cleaner to suck the rag/string through the conduit. It might need a bit of experimentation to get the right balance of plugging the conduit but not being too tight to prevent the suction from working. The more powerful the vacuum the better, but my venerable Henry has always been adequate.

Once the drawstring is through the conduit then it's a far easier job to use it to pull through the required cable(s).

But in this specific case, I think I'd just use standard 20mm plastic conduit to allow for adding additional cables in the future eg an outside light perhaps.