Part 4 - Preparing and installing domestic retrofit system

Question 1

what insulation is suited for each location?

Answer 1

Question 2

whats the things you need to take into consideration when working over ceiling joist?

Answer 2

The ceiling plaster boards are fixed to the ceiling joists, and this is the surface you’re working over.

you need to put some temporary boarding in (Crawler boards), good temporary lighting.

Question 3

what is the desire U-value for insulation at ceiling levels?

Answer 3

This is 0.16W/m2K. 270mm of mineral wool is usually enough to achieve

Question 4

how is insulating ceiling joist done?

Answer 4

Fill any missing patches/gaps in any existing loft material

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Normal practice is to lay the material out in two layers

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The first layer is placed between the ceiling joists (most are around 100mm thick)

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Rather than try and squeeze into the corners of the roof, you can use an extending decorator’s pole to really push the insulation into all the gaps (below).

If there’s a situation where the first layer of insulation is below the ceiling joist, it’s important that additional insulation is used to bring the first layer flush with (or slightly above) the top of the joist

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The second layer is laid over them at right angles across the first layer

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The overall thickness of loft insulation may be as much as 300mm, so now the loft looks like a thick carpet of insulation, covering the joists. Insulated timber loft boards are available and should be fitted after the loft insulation where possible.

Question 5

Why does loft hatches need insulation as well?

Answer 5

not being insulated can lead to cold bridging, draught around the edges of the hatch if they’re not sealed.

100mm insulation board, cut to size and glued to the hatch cover is one option.

The opening will need to be draught proofed, usually done with thin strips of rubber sealing material fixed to the inside of the hatch opening

Question 6

why is the space below the Cold Water Storage Cistern (CWSC) uninsulated ?

Answer 6

Space below the CWSC is left uninsulated to allow warm air to circulate around the CWSC and help to prevent freezing during cold weather

Question 7

What should you consider in regards to electric cable ?

Answer 7

Clipping them out of the way, above and on the cold side of the insulation

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If within the insulation, they need to be sheathed in a plastic conduit that leaves an air gap

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Junction boxes may need re-siting above the insulation

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Groups of cables can be placed inside of larger diameter conduit

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In some cases, it may need an electrician to re-route or rewire the supply.

Question 8

what does insulation pipe work prevent

Answer 8

Cold water pipes freezing in exposed positions during cold weather

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Condensation forming on its cold surface

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Heat loss from hot water pipework.

Question 9

how much insulation do older cylinders needs

Answer 9

80mm

Question 10

Whats the retrofit aim for roofs?

Answer 10

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Adding insulation to improve U-values in a practical manner

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Avoiding thermal bridging of roof members

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Making sure there’s ventilation behind the roof finish (on the cold side of the insulation).

Question 11

How much gap should you have between the ventilated gap above the insulation

Answer 11

50mm

Question 12

what insulation can you choose from in between the rafter?

Answer 12

Rigid PIR, PUR or PF insulation boards with aluminium foil facing

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Rigid EPS insulation boards

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Mineral wool quilts or batts.

Question 13

What insulation can you choose under the rafters?

Answer 13

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Rigid PIR, PUR or PF insulation boards with aluminium foil facing

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Rigid EPS insulation boards

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Wood fibre boards

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Multi foils.