# hard or soft wood



## Nidge3 (May 1, 2005)

I've just ripped down the end 6feet of ceiling as water has been leaking through over the years,the wooden frame is rotten,is it best to replace it with hard wooden batens (very expensive) or treated soft wood?it has also got to be strong enough to take the weight of a air condition unit. 8O


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## 88928 (May 10, 2005)

Hi Nidge,

As a carpenter, I would have to advise you to use hardwood. Softwood (treated or not) will not do the job

Cheers

David


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## 93401 (May 1, 2005)

Hi Nidge,David is right,I am also a Joiner and Hardwood is the way to go,it has a lot more structural integrity and any load will be better supported,Aircon unit etc.cheers Gerry.


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## eurajohn (May 9, 2005)

I do totally agree but I'm sure that most are constructed using softwood.

John.


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## 88797 (May 9, 2005)

Im no carpenter but isnt 'soft' / 'hard' wood a misnomer since balsa is a hard wood? Or am I talking nonsence  

A


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## 88724 (May 9, 2005)

Hi

Balsa is an hardwood, hard is relative term and confusing

George


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## Nidge3 (May 1, 2005)

Cheers Guys


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## 88905 (May 10, 2005)

Softwood comes from evergreens...Hardwood comes from trees which lose their leaves in winter. It's not a relative term nor should it be confusing. Ref: Collins Complete and Unabridged English dictionary

nobby


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## Brambles (May 12, 2005)

Hi,
Afraid I disagree with having to use hardwood. Part reasons are stated above that there are different types of hardwood. 
A good quality softwood free of large knots should be fine. Talk to your local wood merchant and he wil be able to advise on good quality timber and select you some nice straight cuts free from large knots. Probably best go for something like redwood pine. (not sure of proper names like norwegian spruce or whatever).
The main strength does not come from the wood battens but from the sandwich contruction with the skin coverings taking most of the stress and the wood acting as a spacer, so also important to use a quality ply for the ceiling and aluminium sheet, or fibreglass panels for the roof. If the timber will be pre treated but will prolong it's life if retreated should water leak in again. However, the treatment you apply could affect any bonding adhesive you use.
J.


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## 88928 (May 10, 2005)

Well...

Brambles said "A good quality softwood free of large knots should be fine. Talk to your local wood merchant and he wil be able to advise on good quality timber and select you some nice straight cuts free from large knots. "

When did you last visit a local timber merchant and buy timber? 8O 

Regards

Hymercouple


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## 89057 (May 12, 2005)

'IT'S IN AISLE 33 MATE, IT SAYS TIMBER'

Thought I'd save you asking :wink:


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## Brambles (May 12, 2005)

LOL tigger.


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## 93401 (May 1, 2005)

Fancy that,45 years working with timber everyday and its come down to aisle 33,that just about sums it up,B&BQ now everyone an expert,cant wait till Wednesday!regards,Gerry.


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## 93514 (May 1, 2005)

I don't wish to step on the toes of carpenters or joiners but there is no reason why CCA (trade name tanalith etc) treated timber should not be used for this type of repair work on a motorhome.

Treated timber will outlive the motorhome for many generations. The only difficulty has been stated regarding adhesive properties. Obviously, freshly treated timber would need to be allowed to dry for a short period and thereafter any half decent building adhesive should be suitable.

It also goes without saying that the original water ingress problem should be sorted before any repairs are carried out.

BTW for what it's worth, the terms hardwood and softwood refer to plant reproduction and have nothing to do with the density of the timber. These terms have been in use for a very long time, therefore not confusing in the least. 

Hardwood trees are angiosperms, in other words plants that produce seeds with some sort of covering.Softwoods, on the other hand, are gymnosperms. These plants simply allow their seeds to fall to the ground as is, with no covering.

Nobby's explanation covers this adequately, in layman's terms.

Kev


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## 88724 (May 9, 2005)

A few people here are saying its (hardwood/softwood) not confusing, but Just to test I asked the last 10 Adults that I have spoken too, what the difference is, not one got it right, a few knew that Balsa was a Hardwood, but had no idea why, so to the general population the term hardwood and softwood does not make sense.

Most when its explained still think its a silly way to class wood and doesnt make sense.

George


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## 88797 (May 9, 2005)

Trying not to distract from the subject but............. The vast majority of people think that hardwood is strong and soft wood is weak. That is in my opinion the confusion hence my example of balsa as a hardwood. What you need is a wood which will do the job intended irrespective of its type. I did exactly the same thing many years ago and walked into an independent (ie they know what they are talking about) timber merchents and asked for some hardwood. That is like going into a pub and asking for a pint of beer! If you think of hardwood as bitter and softwood as lager and compare alcohol content you see what I mean. 

A


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## Anonymous (Nov 10, 2000)

It's true, it does seem silly, but in O level woodwork I learned that hardwoods come from deciduous trees (lose their leaves) and softwoods come from confierous - woods have been classed this way for well over a thousand years - I don't think a few motorhomers are going to influence things much :wink:

The term actually has nothing to do with the hardness of the wood surface and is believed to originate more from their relative 'hardiness' (i.e. resitance to rot). There are also exceptions to the losing of leaves or not - larch (a confierous softwood) actually loses its needles and some deciduous trees are evergreen. The defining characteristic of hardwood is that the wood has vessels or pores (softwood doesn't) and softwoods have longitudinal resin canals (hardwood doesn't). This is the definative identification criteria.

With regard to their relative rot resistance, again there are exceptions to the hardwood vs. softwood argument - some varieties of American pitch pine have so much resin in them that they are virtually impossible to rot - and to work with(!) - they used to be used in boatbuilding completely unpainted / treated). Similarly, some hardwoods are more prone to rot (ash for example which was / is used in the framing for coachbuilt vehicles is actually quite prone to rot - witness all the moggies you used to see with all sorts of fungus on their woodwork). However, as a broad rule, hardwoods are generally more durable than softwoods and generally have greater structural strength.

If I was going to choose a wood for rebuilding a coachbuilt vehicle, I would choose a durable hardwood (for both rot resistance and structural strength) and if I was going to use sheet materials, I would choose good quality exterior or marine ply. I would also use good quality coachwork specific sealants / adhesives and good working practices (keep the water out in the first place). It'd be a shame to spoil the job for the sake of a few quids-worth of good materials.

There is a very good website about the properties of wood at:

http://www.woodweb.com/knowledge_base/Wood_Handbook.html (American, so some species don't apply, but very well written)

cheers
Matt
(who has spent many years messing around with wooden boats!)


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## 93514 (May 1, 2005)

GeorgeTelford said:


> A few people here are saying its (hardwood/softwood) not confusing, but Just to test I asked the last 10 Adults that I have spoken too, what the difference is, not one got it right, a few knew that Balsa was a Hardwood, but had no idea why, so to the general population the term hardwood and softwood does not make sense.


 :lol: :lol: just don't give up your day job, cause you'll never make it as a pollster. :lol: :lol:

I spoke to 10 adults before posting this and they all knew exactly what I was talking about BUT it wasn't exactly a test nor was it representative of the general population and more importantly I would never go so far as to claim that it was.

Matt, I agree with your excellent summary on the properties of wood and I was thinking along the same lines as larch, cedar etc. when applied to boat building, roof shingles etc.

Kev


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## 88724 (May 9, 2005)

Hi Kev

What it does show is that its not as Obvious as you made it out to be. Now up to 16 adults and one correct answer, a call centre girl.

BTW Randomly ask 10 Non woodworkers and most will not know thats the point, only obvious if you know.


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## Brambles (May 12, 2005)

Sorry guys,

Still stand by my comments to use a good quality softwood like a slow grown swedish or norwegian pine.

You also have to consider the compatibilty with the intended use, and cladding materials, in this case most likely aluminium or Fibreglass.
Taking into acount coeficients of expansion, aging and shrinkage properties, relative strenghths etc it would be a shame to use a strong hardwood which could subsequently result in fracturing of the outer cladding materials. If the casing externally is to be exterior ply of high strength then yes high grade hard woods are fine. But I would not use ply for the exterior - I would be using aluminium or some other plastic sheeting material like fibreglass. The frame has to be weaker than the casing materials to prevent stresses caused by flexing, expansion/contraction etc.

Imagine a very strong 'hard'wood frame with aluminium bonded to it, along comes the frost. Aluminium shrinks, wood frame cannot be compressed along the lengths of timber. What happens - aluminium is stressed and eventually leads to cracks forming. Same for fiberglass panels. 
Softwood is the way to go, with some exceptions of softwoods that are dense and 'hard'. You have to match the materials of the sandwich the best you can. Also do bear in mind the main strength is not in the frame but in the overall sandwich construction. Another aspect is absorbtion of the energy from resonance in the structure. (vibrations). A softwood will absorb the energy better damping the vibrations. A hard wood will not and the panel construction will vibrate better at certain frequencies.
Well, I have said my pennies worth for what it is. I expect a controversial reply but so be it. I am certainly not condemming what others have written - we are all just expressing our views
Oh yes and forget the DIY stores for timber - low grade sap wood and it will have warped before you even get it home, and expensive.


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## 93514 (May 1, 2005)

Good, now it's back on a technical track I would concur with what you say brambles.

BTW keep going George another few call centres and you'll start to get the message :lol: :lol: :lol: 

:roll: such a twit :!: 

(moderators please note I made a conscious effort not to use the letter 'a')

Kev


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## Brambles (May 12, 2005)

somebody please please please remind me what BTW stands for. I just cannot work it out and know I will feel a right 'plank' :? when you tell me.


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## 89146 (May 15, 2005)

By The Way



Gill


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## 88724 (May 9, 2005)

Hi Kev 

As I say and anyone can find for themselves by simply asking around, most people dont get it and even when you tell them it makes no sense to them. If you want to believe it or otherwise fair enough.

PS the list includes

1 Doctor
1 Doctors Receptionist
3 Accountants
2 Bookkeepers
4 IR and VAT inspectors
1 Peugeot Call center girl (only correct answer)
4 Business owners
1 Receptionist at Peugeot
1 courtesy lift driver !

Hopefully your not implying that they are all (bar one) thick for not knowing the difference? Not really what you would call common knowledge.

George

PS Not claiming Mori Poll just a general flavour of what people think


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## peejay (May 10, 2005)

Just a gentle reminder,

This website thrives because of it's reputation for friendliness please help to maintain this reputation accordingly with your posts.

pete.


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## Anonymous (Nov 10, 2000)

Brambles said:


> Sorry guys,
> 
> Still stand by my comments to use a good quality softwood like a slow grown swedish or norwegian pine.....


Excellent points Brambles - my experience is centred around boatbuilding, not coachbuilding and I hadn't thought of some of the issues regarding relative expansion of skin materials and resonance.

I completely agree that a good quality softwood is probably as good as a hardwood in this application (or even better, given your previous points). I suppose that the main thing is fixing the water ingress (in such a way that it will cope with any twisiting and expansion forces), so that whatever wood is used, it's exposure to moisture is minimised. (And then there are vapour barriers and interstitial condensation to consider  ).

Finally I would add that there is probably no way to do this job 'on the cheap' - suitable softwoods (douglas fir / sitka spruce etc) are fairly tricky to get hold of and pretty expensive (at least they were last time I bought some!). http://www.robbins.co.uk/ is a good source of quality timber.

best
Matt


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## Brambles (May 12, 2005)

Thanks Gill - so obvious now - ah well  ,
I feel a right idiot for asking but it has puzzled me for ages.


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## Nidge3 (May 1, 2005)

Hi
I'm sorted,went to a salvage yard and got 40 feet of 4x1 1/2 or 80 feet when I get it sawn down the middle of hardwood for £16 pretty pleased with the price :lol:


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