Pumped cavity insulation and frozen pipes

Cmar-Ireland

Hi folks,

I'm considering getting the cavity in our house filled with pumped insulation. The house is a 3 bed semi with attached garage and 5 years old. Outer leaf is brick up to first floor and dry dash block the rest of the way up. Inner leaf is block with insulated plasterboard.
During the big freeze, our mains water and some rads were frozen. Between the house and garage I can see two qualpex pipes going through the cavity and I suspect the water mains feed pipe in in the cavity of at least passes through and none of these pipes are insulated.

Also the attic space above the garage/utility doesn't have adquate insulation, and there are heating pipes and water feed to the utility sink up there.

I'm thinking that if we get the cavity filled it would help in two ways, firstly it would warm the house due to the extra insulation and secondly the pipes going through the cavity would be protected from freezing.
And if the garage attic space was filled with blown insulation it would prevent freezing

Do you think it's worth doing it for this reason? I'm assuming costs of approx €1000 - €1600 based on quotes that I've read in this forum.

Thanks

stretchaq

any insulation upgrade will help this however be sure when insulating your attic all pipes are also lagged as insulation in the attic can result in pipes freezing easier 100-1600 would be an average price and there are grants availible through www.seai.ie

Cmar-Ireland

I'm curious to know how attic insulation could make the pipes freeze easier? Is it because the insulation would be under the pipes?

air

Cmar - Roof insulation will reduce the amount of heat escaping from the living area into the attic and thus the attic becomes colder for a given outside temperature. As a result the risk of pipes freezing increases.

muffler

Cmar-Ireland wrote: »

I'm curious to know how attic insulation could make the pipes freeze easier? Is it because the insulation would be under the pipes?

Yes, it slows down the rate/amount of heat filtering into the attic.

Traditionally warm air passed through uninsulated ceilings and this heat kept the pipes from freezing....well I dont know if that would have worked last winter or not. Modern building techniques and regulations allow for cold air to pass through the attic by way of vents to reduce the risk of condensation so effectively you could be looking at air temperatures in the attic as low as -10 or more and thats what causes the problems.

You would (or should) have seen water storage tanks in attics which would be insulated around the sides and over the top but insulation is never placed below them. Its the same principle - to allow warm air to reach the underside of the tank.

So insulate your ceilings but never ever forget to insulate the water pipes separately.