DIY Doctor

Insulation of central heating pipes under groundfloor boards

Postby zipster » Sun Nov 30, 2008 5:31 pm

Basic question.
I have a semi with a suspended ground floor wood boards. When I was under the house the other day, I noticed none of the central heating pipes where lagged. Can I do this? Should I do this?
If the answer is yes, can I use basic B&Q type pipe insulation with duct tape? Is this the quickest/cheapest/best solution?

Also when I had the cavity wall insulation done, half of the air bricks under the house were blocked. Should I unblock all of them?

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Simply Build It

Postby matthewm1965 » Thu Dec 04, 2008 12:51 pm

I'm not sure that this is the correct answer as I am not an expert, but My house is exactly the same. Not a single pipe insulated anywhere!

I am going through the house, insulating all the pipes that I can get to. The heat loss from bare copper pipe is quite high. I can't remember the exact figures now, but 70Watts per meter sticks in my mind. It soon adds up to a high wastage of energy / cost.

I am using Wickes byelaw insulation as it is a bit thicker than some of the stuff you can buy.

It is important to insulate any cold water pipes whilst you are at it, as they will no longer benefit from any defrosting effect from the CH pipes.

As for the air bricks. They were put there for a reason. You need some airflow under the floor to prevent damp.

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Postby dannyppp » Sat Dec 06, 2008 2:45 pm

yep best to lag pipes if you can reach them.

Air bricks are there so the air can regulate the moisture content of the timber, preventing wet and most importantly dry rots.

The only problem is that if you have bare floor boards you will have a very draughty house. If the floor boards in your house have approx 2-3mm gaps between each board this should allow a fair bit of ventilation for joists, if not then you could install a couple of vents in the floor in some indiscreet places of the floor to improve the ventilation.

Hope this is of help to you.
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