ᐅ Profiled wooden boards or cladding boards made of plastic above the rafters?
Created on: 23 Sep 2016 10:47
R
RiepiratHello dear forum members,
We are currently planning our single-family house. It will be 1.5 stories with a gable roof.
For aesthetic reasons, we would like exposed collar beams and profiled parent, intermediate, and ridge purlin heads. The roof frame will be made from structural solid timber.
We already have two quotes for this. However, they differ regarding the visible cladding above the rafters.
One provider insists that only profiled wood is suitable here (and apparently cannot offer anything else), as this would be installed on the rafters but beneath the roof battens. Otherwise, they would not provide a warranty. According to them, the expansion behavior between wood and plastic is too different, so plastic cladding boards might break in this case.
The other provider, however, offers plastic cladding boards as the standard solution.
Considering lower maintenance over the years and resistance to weathering, plastic cladding boards actually seem more reasonable to us. It is probably also more cost-effective than having to invest in expensive paint every few years.
What puzzles us is that the first provider rejects plastic cladding from a technical construction perspective and believes it is not feasible. Does the second provider perhaps use different construction methods or have expertise with newer technologies?
We would greatly appreciate your opinions and experiences.
Best regards, Riepirat
We are currently planning our single-family house. It will be 1.5 stories with a gable roof.
For aesthetic reasons, we would like exposed collar beams and profiled parent, intermediate, and ridge purlin heads. The roof frame will be made from structural solid timber.
We already have two quotes for this. However, they differ regarding the visible cladding above the rafters.
One provider insists that only profiled wood is suitable here (and apparently cannot offer anything else), as this would be installed on the rafters but beneath the roof battens. Otherwise, they would not provide a warranty. According to them, the expansion behavior between wood and plastic is too different, so plastic cladding boards might break in this case.
The other provider, however, offers plastic cladding boards as the standard solution.
Considering lower maintenance over the years and resistance to weathering, plastic cladding boards actually seem more reasonable to us. It is probably also more cost-effective than having to invest in expensive paint every few years.
What puzzles us is that the first provider rejects plastic cladding from a technical construction perspective and believes it is not feasible. Does the second provider perhaps use different construction methods or have expertise with newer technologies?
We would greatly appreciate your opinions and experiences.
Best regards, Riepirat
D
Doc.Schnaggls23 Sep 2016 11:17Hello Riepirat,
I can’t help you with the technical differences between plastic cladding boards and profile timber.
Our roof overhangs—including the visible purlins and rafters—are clad with profile timber. Both the home builder and the architect strongly advised against using plastic cladding (which I mentioned) because of the different expansion behaviors of wood and plastic, as you pointed out.
We solved the issue of more frequent maintenance related to painting by choosing to paint the visible timber instead of staining it. While painting doesn’t last forever either, it definitely provides a significantly longer lifespan compared to a regular stain.
However, I have a completely different tip for you:
If you’re actually building with partially visible rafters and purlins, I recommend installing bird deterrent spikes on the top surfaces of those visible purlins (in areas where no rafter is lying on them) while the scaffolding is still in place. This can be done with minimal effort, even by a layperson (the spike strips can be fastened with roofing nails—the strips can be cut to the required length with a decent pair of pliers or wire cutters).
We hadn’t thought of these spikes and were then surprised by the large number of kestrels around us who apparently felt very comfortable on our purlins and "decorated" the windows directly underneath almost daily with unwanted “flying reptile droppings.” Occasionally, half-eaten mice would also stick to our French balconies.
Since installing the spikes afterwards, things have been quiet again—the lovely birds now prefer to sit comfortably on our wood shed and conveniently deposit their “output” somewhere else…
Best regards,
Dirk
I can’t help you with the technical differences between plastic cladding boards and profile timber.
Our roof overhangs—including the visible purlins and rafters—are clad with profile timber. Both the home builder and the architect strongly advised against using plastic cladding (which I mentioned) because of the different expansion behaviors of wood and plastic, as you pointed out.
We solved the issue of more frequent maintenance related to painting by choosing to paint the visible timber instead of staining it. While painting doesn’t last forever either, it definitely provides a significantly longer lifespan compared to a regular stain.
However, I have a completely different tip for you:
If you’re actually building with partially visible rafters and purlins, I recommend installing bird deterrent spikes on the top surfaces of those visible purlins (in areas where no rafter is lying on them) while the scaffolding is still in place. This can be done with minimal effort, even by a layperson (the spike strips can be fastened with roofing nails—the strips can be cut to the required length with a decent pair of pliers or wire cutters).
We hadn’t thought of these spikes and were then surprised by the large number of kestrels around us who apparently felt very comfortable on our purlins and "decorated" the windows directly underneath almost daily with unwanted “flying reptile droppings.” Occasionally, half-eaten mice would also stick to our French balconies.
Since installing the spikes afterwards, things have been quiet again—the lovely birds now prefer to sit comfortably on our wood shed and conveniently deposit their “output” somewhere else…
Best regards,
Dirk
Hello Dirk,
thank you for your detailed and also amusingly written report of your experience regarding the bird issue. It’s really a great read!
The idea of painting is a good one, which we should definitely consider if we decide on wood.
The bird deterrent spikes are also a good idea, and I will add them straight to our long list. We had already seen them on a walk through a new housing development, but we didn’t really think much about it at the time. However, as long as the scaffolding is still there, the effort is actually manageable.
Regarding the cladding boards, the argument about expansion behavior seems to be well known. What surprises me is that plastic cladding boards are increasingly seen in new developments. Either the installers of plastic boards lack knowledge on this, or it is accepted that customers might experience problems, or maybe they have more expertise and use a different technique to avoid potential expansion issues.
This question therefore remains open.
Best regards,
Riepirat
thank you for your detailed and also amusingly written report of your experience regarding the bird issue. It’s really a great read!
The idea of painting is a good one, which we should definitely consider if we decide on wood.
The bird deterrent spikes are also a good idea, and I will add them straight to our long list. We had already seen them on a walk through a new housing development, but we didn’t really think much about it at the time. However, as long as the scaffolding is still there, the effort is actually manageable.
Regarding the cladding boards, the argument about expansion behavior seems to be well known. What surprises me is that plastic cladding boards are increasingly seen in new developments. Either the installers of plastic boards lack knowledge on this, or it is accepted that customers might experience problems, or maybe they have more expertise and use a different technique to avoid potential expansion issues.
This question therefore remains open.
Best regards,
Riepirat
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