Insulated Duct DIY

I need to make up a duct to carry 4 3/4" heating pipes from the garage to the house.
Any ideas

You can buy 4 inch ducts with two 3/4 inch pipes in them, they are also filled with foam. [broken link removed]

you could just buy a few lenghts of 4inch sewer pipe and run two insulated 3/4 pipes in them, you would need 2 runs, or a 6 inch sewer pipe and you might get the four insulated pipes in it.

I would go with option one, because with option two, when the pipes are buried, water will enter pipe (duct) and enter into insulation jacket. once this happens (and it will) then the insulation is as good as useless.

DavyJones,

You can buy pre-insulated heating pipe.It basically has your 3/4 inch flow and return pipe encased in a 4 inch insulated duct.I got mine from Heat Merchants.It is expensive though approx. €45-€55 per linear metre.I think it's worth it rather than heating the ground.

wexford dude said:

DavyJones,

You can buy pre-insulated heating pipe.It basically has your 3/4 inch flow and return pipe encased in a 4 inch insulated duct.I got mine from Heat Merchants.It is expensive though approx. €45-€55 per linear metre.I think it's worth it rather than heating the ground.

Click to expand...

Something like the link in my post, perhaps?

I heard of a guy buying sewer pipe drilling holes every 9 inches, running his pipes through (I presume he afixed them so they would stay roughly in the middle) buying a few cans of insulating foam and put it in through the holes. Alot cheaper then 45 euro a linerar meter. Just any idea not sure how it worked