Pipework: Notching and/or Drilling Joists vs over the top?

paperclap

Hi all,

I am replacing our radiators and pipework.

Our current setup consists of two rads sharing one drop down leg, and another two rads sharing another drop down leg (tee’d off at the bottom of the legs, of course).

When fitting the new rads, two will be positioned the same as their predecessors. However, the other two will be relocated. Because of this, they can’t share the same drop down legs as they once did… and will therefore need their own drop down legs.

In the loft (bungalow), the current flow and return pipes are suspended in the air by about one foot, supported by small bits of wood.

As each rad will now need its own drop down leg, I wasn’t overly keen on the idea of now having multiple tee joints flying off to each drop down leg along these pipes.

In short, is it best to relocate these pipes in the loft, rather than having them suspended, as they currently are?

I don’t think I can drill through the joists, as it would be practically impossible to feed any decent length of pipe through multiple joists.

Im not keen on notching the joists, either. The last thing I want to do is to upset the structurally sound balance of the house!

Alternatively, is it an idea to simply sit the pipes on top of the joists (sitting in talon clips)?

All of the above options raise the question of: how do I then insulate / lag the pipes?

Any thoughts or recommendations?

Thanks.

grumbler

laurencewhymark said:

I don’t think I can drill through the joists, as it would be practically impossible to feed any decent length of pipe through multiple joists.

Very easy if you use plastic pipe.

Im not keen on notching the joists, either. The last thing I want to do is to upset the structurally sound balance of the house!

Not a big deal if it's close to the wall, but in any case, it's the load bearing capacity of joists only that is affected.

FreeBear

laurencewhymark said: Alternatively, is it an idea to simply sit the pipes on top of the joists (sitting in talon clips)?

All of the above options raise the question of: how do I then insulate / lag the pipes?

Yes, always route the pipes above the joists rather than notching or drilling holes. Use a few clips to hold them in place, and then insulate. The more insulation, the better, so use the thick stuff rather than the cheap £1/length from Screwfix.

paperclap

FreeBear said:

laurencewhymark said: Alternatively, is it an idea to simply sit the pipes on top of the joists (sitting in talon clips)?

All of the above options raise the question of: how do I then insulate / lag the pipes?

Yes, always route the pipes above the joists rather than notching or drilling holes. Use a few clips to hold them in place, and then insulate. The more insulation, the better, so use the thick stuff rather than the cheap £1/length from Screwfix.

Thanks FreeBear!

But, if the pipes are in 15mm clips, how can they then be insulated?

grumbler

Well between the joists + somehow above them? My understanding is that the loft isn't boarded.

paperclap

Correct Grumbler, the loft isn’t boarded

Norman_Castle

laurencewhymark said:

But, if the pipes are in 15mm clips, how can they then be insulated?

Cut the insulation to fit around the clip.

grumbler

Also, depending on the outside diameter of the insulation, you can consider using waste pipe clips (40mm) instead or even those for guttering downpipe (68mm).

paperclap

grumbler said:

Also, depending on the outside diameter of the insulation, you can consider using waste pipe clips (40mm) instead or even those for guttering downpipe (68mm).

You’re thinking of insulating the pipes, and then nesting the pipes (with the insulation) in the clips?

grumbler

Yep. Why not? As the insulation is soft, the clip diameter can be a little smaller.

Alternatively you can DIY similar 'clips' from steel wire (fixable with two screws).

paperclap

grumbler said:

Yep. Why not? As the insulation is soft, the clip diameter can be a little smaller.

Alternatively you can DIY similar 'clips' from steel wire (fixable with two screws).

Not a bad shout!