Re-roofing a Lockwood house - can I and should I install insulation

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PolicyGuy

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#248493 28-Mar-2019 14:09

I own a 1979 Lockwood house with a longrun-type steel roof which is showing signs of distress, so I am considering a re-roof.

I imagine that the roof construction consists of battens running horizontally across the top of the solid timber Lockwood plank ceilings, with the steel secured directly onto these battens. Maybe there is a plastic (or tarred-paper?) membrane in there somewhere? What size would the battens be - 50x25mm / 2x1"?
I'm almost certain there is no specific insulation, although of course the ~75mm thick planking has significant insulation value.

Any ideas on where to get some information on the way Lockwood house roofs were built in the late 1970s?

If I have to re-roof - which seems likely - then maybe it would be possible even desirable to install some insulation after the old steel comes off and before the new steel goes on.
Ideas that I have thought of include

adding a relatively thin layer - 20mm or so - of rigid foam, or
doubling up the battens with either another 50x25mm / 2x1" giving an extra 25mm gap or a 50x100mm / 2x4" giving an extra 100mm gap. This would allow thicker rigid foam or maybe fibreglass wool [incl Pink Batts(tm)]

Has anyone done this or heard of anyone doing this kind of crazy thing?
Where would I get advice on this?

trig42

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#2206285 28-Mar-2019 14:16

I don't know that I would bother.

We have an Initial home, so don't have the timber ceilings, but the outside walls are the same as what your ceilings would be. We have no insulation in the walls, and have not felt the need for it. The house is warm in winter and cool(ish) in summer. Our ceiling is insulated, but only batts in the attic (we have a gib ceiling with attic space).

Our house is only 11 years old, so obviously there was no need (building inspection wise) for insulation when it was built - the wood must be sufficient.

Quoban

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#2206286 28-Mar-2019 14:21

I am renovating a 1987 Lockwood in Auckland.

I purchased the property file from Auckland Council, which included the house plans and specifications of the Lockwood design at the time.
It isn't the easiest to read, but I've attempted to provide the clearest picture possible.

I'm planning on lowering the ceilings by approx 20-30cm, same pitch (4m+ high), to add insulation and downlights. Might be an option for you, depending on ceiling heights already.

I have also sent Lockwood a few emails - info@lockwood.co.nz
They're pretty quick responding with lots of helpful information.

timmmay

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#2206322 28-Mar-2019 14:37

There should be tar paper or similar in there, otherwise you'd have water in the house.

You have to be careful putting in insulation, there may be building code issues. For example, if insulation is pressed against the tar paper will that let water in? I have no idea what the answer is to that.

I'd suggest you give Lockwood a call for their opinion, and then call the council before you do anything. An unconsented modification could make selling difficult.

Lowering the ceiling to add insulation would be expensive, but ceiling insulation can make a big difference.

wellygary

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#2206325 28-Mar-2019 14:44

PolicyGuy:

I own a 1979 Lockwood house with a longrun-type steel roof which is showing signs of distress, so I am considering a re-roof.

I imagine that the roof construction consists of battens running horizontally across the top of the solid timber Lockwood plank ceilings, with the steel secured directly onto these battens. Maybe there is a plastic (or tarred-paper?) membrane in there somewhere? What size would the battens be - 50x25mm / 2x1"?
I'm almost certain there is no specific insulation, although of course the ~75mm thick planking has significant insulation value.

Where would I get advice on this?

I think you may be treading a well worn path, so much so that Lockwood have this info....

https://lockwood.co.nz/wp-content/uploads/2018/08/RetroFitInsulationGuide_LockwoodHomes.pdf

I would also talk to your local council about what consents/sign offs you might need for such a project

PolicyGuy

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#2206361 28-Mar-2019 15:42

wellygary:

PolicyGuy:

I own a 1979 Lockwood house with a longrun-type steel roof which is showing signs of distress, so I am considering a re-roof.

I imagine that the roof construction consists of battens running horizontally across the top of the solid timber Lockwood plank ceilings, with the steel secured directly onto these battens. Maybe there is a plastic (or tarred-paper?) membrane in there somewhere? What size would the battens be - 50x25mm / 2x1"?
I'm almost certain there is no specific insulation, although of course the ~75mm thick planking has significant insulation value.

Where would I get advice on this?

I think you may be treading a well worn path, so much so that Lockwood have this info....

https://lockwood.co.nz/wp-content/uploads/2018/08/RetroFitInsulationGuide_LockwoodHomes.pdf

I would also talk to your local council about what consents/sign offs you might need for such a project

Thanks, wellygary, that is indeed the exact thing I need 😀