NOMADICISTA

Hello everyone, been a while since ive visited the forum so hope this question finds you well.

A brief question concerning the use of different types of wood (hardwood/softwood) for different applications throughout the build of my housetruck.

All of the interior uses redwood pine, mainly as its all i can afford. I have recently got some new windows that i wanted to frame in pine between the aluminium siding of the vehicle and the ply lining interior.

I have been told that even though the pine frames will not be exposed directly to weathering and rain over time i could have problems with mould and wet rot arising from contact with condensation from the metal and possible leaks through screw holes and seals etc. I was advised to use a hardwood but its drastically more expensive. Is this nonsense?!

Is using pine for this purpose going to be troublesome for me in months/years down the line or will it be just fine. If so would i need to treat the pine with either a varnish or wood preserve or can i just screw it in untreated without problems. OR should i just settle for a hardwood, if so can anyone recommend something cheaper than oak which costs £170 for 10 meters.

Thanx guys.

Dan

Hi Dan. I assume by "redwood pine" you are not referring to Sequoia sempervirens, also known as "Coastal Redwood" or "California Redwood". This species of softwood would be an excellent choice due to it's close, clear grain structure and it is almost impervious to rot and bugs.

The "pine" I am familiar with here in the US is very soft, somewhat pitchy, usually filled with knots, and doesn't stand up to weather very well. It's also difficult to protect with top coatings (varnish, paint) due to the oily nature of the grain. It is also very difficult to seat fasteners into securely.

Oak would not be my choice for an exterior hardwood. It has very porous, open grain which would tend to wick up moisture. Exposed Oak actually rots fairly quickly. It's also somewhat cantankerous to work with, as the grain is large and frequently contains faults.

When I built the skylights for the Housetruck, I chose Philippine Mahogany as a "middle ground" hardwood. It has close grain, is available in clear (knot-free) lengths. It is easy to work and takes fasteners well. While it is susceptible to moisture rot and wood boring organisms, it takes preservatives well. Lots of brightwork on boats is made of mahogany.

Of course, if you are looking for the ultimate in exterior wood, teak would be the best choice. It is very hard, but close grained and has an oily consistency, so much so that preservatives are only needed as an appearance enhancement.

Teak sounds expensive, but in many parts of the world, it's a "throw away" species. Crating and freight dunnage is made from less choice bolts of teak. You can frequently find scrap timbers of teak around boat yards and shipping ports, it's used to secure shipments from moving during travel.

Whatever you use, you probably won't be needing very much of it to make a few windows, so if you have to purchase it, it won't be especially dear. The biggest expenditure is your time to construct, finish and install the items, and making sure you only have to do it once is important.

[edit] After blabbing on a great length about building your windows, I posted and then went back and re-read the original post, and now understand that you are looking for wood to frame your windows. Duh. Well, I'd be hard pressed to recommend going all-out with hardwood in this application.

What do carpenters over there use to build exterior structures, stairs, flower boxes, retaining walls, etc? Over here we have a variety of outdoor woods all of which are chemically-treated Douglas Fir or Hemlock Fir, referred to generically as "pressure treated" or by a variety of brand names like "Sun Wood".

If you don't want to install treated wood in your truck, consider something like the Doug Fir with some preservative on it. I used Fir to frame the Housetruck windows thirty five years ago and they aren't (quite) falling out yet.

I'd say your selection should be one that holds fasteners well, doesn't tend to crack when screwed into, and takes paint well. The Coastal Redwood still sounds good to me if you can find it. It's so common on the West Coast here that they build fences out of it... [/edit]

I like the few top grade mahoganies for anything that will be exposed to the elements even if it’s going to be painted. There is also a poor mans mahogany type wood called cedro ( not sure of the spelling ) It’s Spanish cedar. It’s much harder then pacific red cedar. It’s a nice clear vertical grain red wood like good mahogany and cheaper per board foot by a dollar or more. The only thing I could say bad about it is that if it’s put to the weather without a finish on it will bleed red for a while so I would say seal it up good and you will have windows and door for many years. There is also a poor mans teak, Ipe is a very dense hard wood. It’s primarily used for decking and large commercial boardwalks. I’ve made a few custom pieces of furniture over the years with it. It’s very hard to work with in that it’s incredibly hard and will need to be drilled and screwed and glued with a good epoxy ( I like West system ) As a finish for exterior I would use a product call “Sikkensâ€

I would guess that the condensation problem will be an issue for the timber framing throughout your wagon because of the aluminium cladding. My guess would be to treat the timber with an appropriate preservative, and not worry about using hardwood framing. When I smashed up my old touring caravan to recover the scrap metal, the timber structure (untreated 2"x2") had rotted in some places, but this looked to have been caused by external leaks rather than condensation. This small caravan had been used as a full time home for a total of seven years, and must have been around thirty years old. What I'm trying to say is that although condensation may cause a little damage to redwood framing, it is probably nothing to worry about.

Thanks for all your advice guys. Much appreciated!

After being somewhat reassured from your replies ive opted for the softwood option. The wood is Scandinavian Redwood (Pinus sylvestris), stocked at Travis Perkins and is used extensively for timber construction (apparently takes wood treatments well). Its costs about £1.90 per meter as opposed to my other hardwood option Meranti which was £10 per meter.

Given my current financial situation...its a no brainer!!

Dan