Basic domestic retrofit installation skills

Question 1

What is Calibration ?

Answer 1

This relates to the use of cavity wall insulation injection machinery. A daily calibration check should be carried out to ensure that the blowing machine pressure switch is operating correctly.

starting the engine and inserting the nozzle into a hessian bag. Then blowing wool into the bag whilst watching the blowing pressure gauge. The nozzle should be blocked off gently inside the bag. Blowing should cease when the gauge registers 260 - 280 mbar

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Adjusting the switch if required. To adjust, use a small screwdriver and turn the screw in to increase the pressure and out to lower the pressure.

Question 2

Why is sealing important?

Answer 2

This is really important in preventing the passage of air and moisture, and it prevents thermal bridging.

Question 3

What is the finish of external and internal wall insulation?

Answer 3

involves fixing a layer of insulation material to the wall, then covering it with a render or cladding. The finish can be smooth, textured, painted, tiled, panelled, pebble-dashed or finished with brick slips.

Internal wall finishes are is usually completed by a plaster skim.