Best way to insulate a series of pipes which are fastened to joists in compact attic space

dave_1982

I'm in the process of insulating an attic space in the back annex of a house that I recently bought and moved in to. There are lots of water pipes running parallel towards the hot press and they are all fastened to the joists with nailed in brackets. The pipe is nearly all a Flexi plastic piping (qualpex). I've been told that all pipes should definitely be insulated to avoid bursts. There is an existing 100mill of fibreglass insulation between the joists and I plan on rolling out another 200mill on top of this (Rockwoll from B&Q).Attached is a photo of the main section of pipes. I have two questions.

1. Do I need to insulate all pipes individually with foam pipe insulation or could I just roll the 200mill rockwool right over these for the same effect?
2. If I do need to individually insulate each pipe with foam insulation how do I manage all of the couplers and white brackets attaching pipes to joists? Do I just cut the foam to cover each section and leave the couplers/brackets exposed?

Any advice on how to do this would be greatly appreciated. I don't mind taking time to do each pipe individually if that is ultimately the best way to do it.

Dave

10-10-20

Looking at that setup- if it was me I'd just run a good layer of glasswool over the whole lot but putting it under the horizontal cables. Either 100 or 150mm. Frankly you could probably top-up the whole attic with runs perpendicular to the joists while you're at it. Job done.

I'd also comment that you appear to have a significant ingress of air around where that existing yellow glasswool is black. Investigate this as it's potentially a sign of excessive ingress at this point (and are you near a road?). The air ingress should be even across the attic space and the attic should be properly ventilated, but I'd just be of the opinion that this point may be problematic.

dave_1982

Thanks 10-10-20. That's really useful. Running a layer of glasswool over the whole attic makes sense and if this means not wrapping each pipe individually it will save me a lot of hassle and time.

The cleaner glasswool in the foreground of this pic is newer insulation that I've just put in. When I first went up there after buying the house there was a layer of what looked like really old glasswool over the entire space and it was all quite black generally. What you see towards the back of this photo is the remnants of that glasswool. I am near a road and I'm very close to the town centre so there is plenty of traffic nearby.

When you say this could be problematic do you suspect that there may generally be too much air getting in at the soffits generally or perhaps at one particular place?

Thanks again for your advice

10-10-20

Ok, that makes more sense. If most of the original glasswool was all blackened then that's pretty normal. It's possibly combustion particulates from road traffic and smoke, etc.

But you will generally find that any glasswool which is within an air-flow and near a road will pickup and cling to any dust within the air. As glasswool becomes more dense with this dust it becomes less effective. Bag it and bin it, then layer-up as mentioned above. Best investment by far.

Don't forget to protect the cold-water tank by leaving the area under it exposed... or if you're into a bit if DIY - build a wooden frame around it and then clad it with glasswool to also protect it.

Lastly, price up rockwool/glasswool from multiple suppliers such as Brooks, Chadwicks and Goodwins and B&Q etc, as there is a significant saving to be made from shopping around. Don't forget to price it by the m^2 rather than by the roll as different vendors supply different coverage per roll.

Effects

Insulation for pipes costs next to nothing, and is easily installed.