Insulating Central Heating Pipes in Loft

18 Jul 2007
Reaction score
United Kingdom
My boiler is in the garage and the central heating pipes run upwards into a loft space above the garage, and from there they run into the house. The pipes look like they were originally insulated in a fibrous material which was wrapped round and round the pipes like tape, however most of this is now missing and hence the pipes are now minimally insulated.

Firstly, before I start, is this stuff likely to contain asbestos? If I'm not sure how can I find out?

Secondly, I'd like to re-insulate the pipes before the winter comes. The flow and return are both 22mm and are run parallel to each other, almost touching along the entire length. The existing insulation was wrapped around both pipes thus enclosing them together. The pipes are too close together to insulate them together with conventional foam lagging, so I was wondering about something like ThermaWrap Spiral Wrap Tape. Is this a sensible option given what I have? It feels like bad practice enclosing the flow and return together as I assume I'll be artificially heating the return to a degree? Is that an issue or am I overthinking it? is there a better option to the spiral wrap tape, short of replumbing with a sufficient gap between the pipes?
Sponsored Links
Generally asbestos pipe insulation is white and tended to be used on larger installations such as hospitals and schools, often with a smooth finish that resembled Plaster of Paris. There are lots of photos on line so you can see what it looks like. What you describe sounds more like Stitched Pipe Wrap which is still readily available. But has poor insulation properties, and can fall off and gap if not installed properly.


Foam pipe insulation is better than the wrap around type as it offers better insulation and won't form gaps. It has a preformed slit that will allow it to be fitted over installed pipes and a few cable ties will keep it in place, keep the ties loosely fitted so they don't squash the insulation. The thicker the foam better, although you may be restricted if pipes are installed close together. Sometimes it is necessary to trim one side of the insulation so they can butt up to each other.

Drawing1 Model (1).jpg
Last edited:
Thanks, that stitched pipe wrap looks just like what I've got. I did have a Google but clearly wasn't searching for the right words!

If foam insulation is a better way to go, I'll go with that. I haven't measured but from what I remember last time I was in the loft, the pipes are probably only 5mm apart so I'll need to cut away a fair chunk of the insulation to allow them to fit.

I assume I'm still best off buying the thickest insulation I can get? I'll obviously have to cut away more to make them fit but there'll still be more insulation around the overall outer?

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links