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Under our north-facing deck ‘tin’ roof it can get a bit hot.

And in this years sweltering Summer(hottest summer on record) it was particularly bad.

As you can see from the photo of the thermometer attached to the roof, the temperature under here can reach 40 degrees celcius.

It was time to do something about it.


We had talked about insulating the deck roof for some time, so when Bunnings had plywood on special we thought we should get it done.

We purchased some 6mm non-structural plywood and some R 1.8 Metal Roof insulation, and planned to insulate and enclose 3 ‘sections’ of the roof.

Those 3 section are directly above the table on the deck where we spend most of our time.


We may do some more ‘sections’ over time, but this will be enough to make a big improvement in comfort over summer under the ‘hot tin roof’.

Temperature of the deck roof
Insulating the deck roof
Metal Roof Insulation

As the majority of the heat transfer under the roof was ‘radiant’ we chose a foil-backed recycled glass wool insulation.

The insulation was rated at R 1.8 and is 75mm thick.

This would fit between the rafters easily and into the batten areas right under the roof sheets.

We stapled the insulation up into the rafter spaces and despite losing the odd bit of insulation wool it fitted and held well. Then it was just a matter of cutting down the plywood to size and then fixing it in the ceiling spaces.


This was not quite as easy as we thought it would be as our house is not exactly ‘square’.  Consequently the sheets were cut to a ‘best fit’ the rafter spaces.

This left us with some gaps at edges, and some very tight fits in other areas.

We trimmed the tight bits to make them fit, and filled the larger gaps with a paint-able silicone sealant.

The first section was finished without too much hassle and we will complete the other sections in the next few days.

Insulating the deck roof
Insulating the deck roof



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