Lagging/insulation for pipes

[my_name_is_slim_daisy]

Good evening all

Hope you’re doing well.

With subzero temperatures approaching I realised that I haven’t yet tackled the issue of preventing pipes from freezing/bursting… and so it goes right to the top of my priorities.

I’m not quite sure which pipes I should insulate, but here are the ones I think I should insulate…

1. The exposed pipes in the loft (mixture of copper and plastic).. I went up there to clean recently and it looks like the plumbers just ripped up the lagging to access the pipe work -and they didn’t replace it (the lagging did look very old to be fair). I am planning to get loft insulation in by the end of the month (~270mm) which would sit close to (and potentially hug) some of the pipes. Should I re-insulate the pipes despite the imminent loft insulation?

2. Pipes under the suspended floor. I’m sure these are almost entirely central heating pipes and I think I should lift the boards and insulate them asap. I will have the combi configured to a min temp of 15 degrees, but that’s more about room temp rather than pipe temp? (Apologies if I’m being a bimbo).

3. Pipes inside the property that run along the external walls. I should get them insulated right? The brick work must be at least 9inches thick but I imagine indoors could still drop to subzero temp? (Sorry it’s my first property)!

4. The outdoor tap will definitely get insulated - but what do folks here use? I’m reading mixed reviews about some of the insulating products

Apologies for rambling on and on. I’d really appreciate your experience and expertise .

Thank you

 

[a twig]

Some quick thoughts:

1. Just whack some of the cheapo foam stuff over the pipes and then you’ll be ok, then once the loft insulation is down nothing to worry about

2. These should be fine from an external temps point of view - I’d make this a lower priority and do it as and when you have the floorboards up for other jobs

3. If your heating is functional then the boiler will be kicking in long before the pipes in the rooms get to sub zero temperatures

4. The traditional approach was to leave the tap running ever so slightly through the winter as the movement of water would prevent freezing but that sort of thing is frowned upon nowadays.
Next option is shut it off from an internal stopcock / valve and then leave the tap open over winter. Otherwise pick the insulation product for garden taps that has the best star rating in the reviews

 

[Stevers]

If you have any tanks in the loft (and with a combi you shouldn't), insulate over them, not underneath them. Same sort of principle with pipes, but again why have pipes in a loft when you have a combi?

 

[a twig]

We still have pipes in the loft from when the combi was retrofitted as it was less intrusive than running whole new plumbing circuits and our combi is in the upstairs bathroom

 

[Cubist]

Can I ask a dumb questions of Daisy(?) please?

How old is this house and how long has all that pipework been in place?
Will the CH system be running throughout the coming winter or the house left unoccupied for a protracted period?

 

[my_name_is_slim_daisy]

Can I ask a dumb questions of Daisy(?) please?

How old is this house and how long has all that pipework been in place?
Will the CH system be running throughout the coming winter or the house left unoccupied for a protracted period?

Thanks for all your responses… I’m in the process of insulating the pipes in the loft!

The house is c.1920 Edwardian with suspended floors. Not sure how old the pipe work is, but there’s a plastic cold water pipe that seems to make its way from the under stairs cupboard, up to the bathroom and then into the loft. It then joins to copper pipes which feeds into the airing cupboard where the new combi boiler is.

I plan to run the CH at around 15-17 degrees throughout winter - I’m ill prepared for winter and I’ll just have to take the hit on my gas bill .

Definitely won’t be unoccupied with the state it’s in - i need to keep a close eye on the house as I don’t trust it (or it doesn’t trust me) yet!

@Stevers I had a Vaillant combi boiler installed recently - the cold water tank in the loft was emptied and disconnected but remains in situ. I’m planning to layer some insulation in the thank as little old me couldn’t possibly move a 50-60kg tank myself - and I worry if I move it, it may fall through the floor!

@twig thanks so much for taking the time to respond - it’s super helpful and I’m already on it. The downside is I can’t seem to find a shut off valve for the outside tap. I’ll have to just really wrap it up well and hope for the best through winter

 

[my_name_is_slim_daisy]

@Cubist no problem… not a dumb question at all… just have a read of what I’m asking!

As a new home owner I have to ask these daft questions unfortunately. The info on the internet is always conflicting, and folks on here are very sensible/experienced. So happy I’ve found this community!

 

[Cubist]

Hi Daisy,
My father taught me that the only really dumb question is the one that was never asked, and, that there is only one mistake anyone can ever make and that's the same one twice.

With these answers your risk should be very low and only associated with the pipes in the loft. All the others are in heated parts of the house where there is little to no risk of any freezing. As you are already dealing with those as per suggestions from other members detailed above I think you can relax. I certainly wouldn't bother trying to shift the now redundant tank in the loft at any time now or in the future - unless you want to use that space or sell the darn thing. In any event its unlikely to be as heavy as you think, unless its full of water and silt, but the steel ones can be very cumbersome.

The routing of the pipework from the understairs cupboard to the bathroom and then into the loft is typical but the leg from the bathroom to the loft should now have been cut off. That cold water tank in the loft would have originally supplied water to some/all the cold water taps and fed the hot water cylinder in a bedroom level airing cupboard, which is also now redundant.

Aside then from the pipes in the loft your biggest internal water risk is the age of the pipes and the possibility of them springing a pin-hole leak somewhere - but that's a very remote one.

Relax and enjoy the holiday to come, it sounds like you may have a lot of other work to be getting on with. Good luck and please come back if there is anything at all you're unsure of, theres always someone here willing to step up and help out.
Cubist

 

[Flyfisher]

My father taught me that the only really dumb question is the one that was never asked, and, that there is only one mistake anyone can ever make and that's the same one twice.

Wise man and spot on. We're not born knowing this stuff so how else are we supposed to know? The only dumb thing is not to learn.

The only thing I'd add to all the above is that insulation can only slow down the rate at which heat is lost (or gained) whenever there's a temperature difference. If the ambient temperature remains below zero for a long (ish) time and the water in the pipes is static then even insulated pipes will eventually freeze.

In practice, the water in most pipes is not completely static as normal daily living means a fairly constant, if intermittent, flow of water and even though mains water will be cold it will mostly be a lot warmer than a freezing UK day (maybe less so in t'north ), so the point of insulation is to reduce the rate of cooling so that the water in the pipe won't freeze before the next incoming rush of (relatively) warm water flushes through. Added to that, it's fairly uncommon for daytime temperatures to remain below freezing as well as nightime, so daylight brings a (relative) warming phase (albeit slowed down by the insulation!). But of course there are always bouts of extreme cold weather. Also, if you're going away for a week or few during a very cold spell of weather then it's a good idea to turn off the mains water (but not the heating - even when 'off' the system should have a default frost protection setting).

Where water is likely to be static, eg in outdoor tap pipework, it's not really necessary to insulate the pipes or taps if they can be easily drained instead. I don't bother with insulating our outdoor taps because I've fitted them with an indoor lever valve, which I turn off in winter and then open the outdoor tap to let the water drain out. Any residual water will likely freeze at some point but because the pipe is now open to the air the ice pressure cannot build up and damage the pipe or tap.

 

[Cubist]

To add to Flyfishers thoughts; as your primary water services are no longer served via the pipes in the loft these should be dry right now and therefore be no problem. Any pipes associated with the CH system that may be routed through the loft will not be a problem either as these will be flowing with hot water.

 

[Stevers]

Any pipes associated with the CH system that may be routed through the loft will not be a problem either as these will be flowing with hot water.

Considering the damage that a water leak can cause, it would probably be sensible to provide some protection for when hot water isn't flowing; there could be a number of reasons for that, including absence and breakdown of boiler, pump or controls. Insulation over the pipes rather than under would be a good start.

 

[my_name_is_slim_daisy]

If you have any tanks in the loft (and with a combi you shouldn't), insulate over them, not underneath them. Same sort of principle with pipes, but again why have pipes in a loft when you have a combi?

@Stevers I might seem a bit thick asking this, but you mean lay the insulation inside the empty tank? I’m not even going to lift it so won’t be putting any insulation under it for sure. So I am going to lay insulation in and around it

 

[my_name_is_slim_daisy]

I think the plumber said the cold water mains pipe is still running through the loft… when I follow it, it drops down into the boiler room and feeds into the combi boiler.

 

[Stevers]

you mean lay the insulation inside the empty tank?

Not the empty tank no, just don't add water!

 

[Cubist]

I think the plumber said the cold water mains pipe is still running through the loft… when I follow it, it drops down into the boiler room and feeds into the combi boiler.

That's really odd. There is a rationale to explain it but I am a trifle puzzled nevertheless.

Are your hot water services provided by the combi boilers Direct Hot Water (DHW) capabilities?

If yes, then your plumber simply took the line of least work and connected the mains water service feed to the combi boiler using a new section of pipe that he ran from where he cut the supply to the tank in the loft or, more likely perhaps, from the feed to the old hot water cylinder in the airing cupboard. Either way, this means that there is a pipe running through the loft space that is carrying mains pressure cold water. Clearly this must not be interfered with and needs to be insulated.

Has the old hot water cylinder been removed?

 

[lizziecupcakes]

If you have any tanks in the loft (and with a combi you shouldn't), insulate over them, not underneath them. Same sort of principle with pipes, but again why have pipes in a loft when you have a combi?

Hi @Stevers - this is interesting. I have a cold tank in my loft too but it’s disconnected because we had a new combi boiler put in. They didn’t remove the cold water tank because it was too big to fit through the hatch.

I’m doing my loft insulation myself next week. I can’t get under the tank (too heavy), so do you recommend I just cut pieces of the insulation and lay them around the outside of the tank? Would this work?

Should I just lay it over the top, or find a way to secure/stick it to the sides of the tank too? I’m not sure how far to go with it.

There’s already about 100mm of insulation between the joists (done by the previous owners) but I’ve definitely noticed tha bedroom that’s under where the cold water tank is, losses heat a bit quicker than other rooms. I think it’s the lack of insulation under it, so I’m quite eager to find a solution.

Although it’s not a container, I’ll be doing something similar with the loft hatch (cutting the insulation to size and sticking it on somehow so it doesn’t fall off everytime we open/close the hatch).

Can anyone recommend how I can also keep the insulation in place that will cover the hatch please?

 

[Cubist]

Put a lid on it and wrap up LCC (|the tank that is) and stick some insulation to the back of the hatch while you're at it.

 

[jamest]

You can buy some rigid insulation and stick it on top of your hatch: I had some insulated tile backer board - marmox board - left over and used a couple of layers of that on one of my loft hatches glued on with OB1 - easy, cheap, reduced the waste and did the job. On one of the others (I've got three) I built a little box with plywood (with the hatch as the base) and filled it with left over quilt type insulation that I had and then put a plywood top on it. Slightly more difficult to do, but equally effective.

 

[Cubist]

You can buy some rigid insulation and stick it on top of your hatch: I had some insulated tile backer board - marmox board - left over and used a couple of layers of that on one of my loft hatches glued on with OB1 - easy, cheap, reduced the waste and did the job. On one of the others (I've got three) I built a little box with plywood (with the hatch as the base) and filled it with left over quilt type insulation that I had and then put a plywood top on it. Slightly more difficult to do, but equally effective.

Or alternatively, cut a couple of pieces of timber from the planks you're taking out of the loft and use them to bridge the tank - saves a bit of effort lugging em downstairs too.

 

[LadyArowana]

You can buy some rigid insulation and stick it on top of your hatch: I had some insulated tile backer board - marmox board - left over and used a couple of layers of that on one of my loft hatches glued on with OB1 - easy, cheap, reduced the waste and did the job. On one of the others (I've got three) I built a little box with plywood (with the hatch as the base) and filled it with left over quilt type insulation that I had and then put a plywood top on it. Slightly more difficult to do, but equally effective.

I wouldn’t want anything very heavy on top of our loft hatch, it’s already a bit of a beast to lift and anything board wise might increase that, but depends on the setup the OP has