RV wood framing, types of lumber used

[shermy1987]

Hi to all.

Does anybody know what common types of 2x2 lumber is used for constructing RV walls?

I can find so many posts about wood vs aluminum etc, yet nothing about what actual types of wood is being used in modern RV framing construction.

[seaeagle2]

I think they use the pallets they get deliveries on for some of it

[bartlettj]

Yeah, I snapped the shank off my favorite 3/4" auger bit today while boring a hole through a fir 6x10 to install a new hose bib. I think that one piece of timber is probably enough board feet to build a couple 5th wheels out of.

[BobsYourUncle]

bartlettj wrote:

BobsYourUncle wrote:

Fir gets very hard with age and is more prone to splitting with flexing and movement. That's one of the reasons fir is not suitable for RV application.

I have a house built in 1895 out of old growth fir. I've been doing some remodeling, and if I want to reliably sink a nail or screw into a stud without breaking the fastener, I have to either use a nail gun, an impact driver, or predrill.

I've reworked some really old fir over the years too. Remember when 2X4's were 2" X4"?
Yeah it can get pretty hard alright! Even with my Bostitch N80 coiler set at 120 PSI it still won't run the nail all the way in. Gotta follow it with a 28oz Estwing and all that does is bend the head over!
Tough stuff!

[bartlettj]

BobsYourUncle wrote:

Fir gets very hard with age and is more prone to splitting with flexing and movement. That's one of the reasons fir is not suitable for RV application.

I have a house built in 1895 out of old growth fir. I've been doing some remodeling, and if I want to reliably sink a nail or screw into a stud without breaking the fastener, I have to either use a nail gun, an impact driver, or predrill.

[bartlettj]

goducks10 wrote:

Hammerboy wrote:
Go to the lumberyard and ask for #2 pine 2x whatever,rip it to size, (you need a table saw anyway 😉 that's all it is and can be found everywhere.

Dan

Except on the west coast where Fir reigns supreme. All we have out here are 1x's in pine.

Actually, I see a lot more hemlock and douglas fir as structural lumber (Oregon and Washington), and it's usually hemlock. True fir is usually reserved for millwork.

[delwhjr]

NMDriver wrote:

Ivylog wrote:
The cheapest soft wood they can buy...rarely is it pine and never pressure treated.

X2 and luan for the roof decking.

I suspect cardboard would be used if they could get it to last until the warranty expired.

Watch what you say about cardboard. I have a friend who works for a cardboard manufacturer and he showed me where they are working on cardboard studs. He claims they will be stronger than a normal 2x4.
So who knows!:E

[goducks10]

Hammerboy wrote:
Go to the lumberyard and ask for #2 pine 2x whatever,rip it to size, (you need a table saw anyway 😉 that's all it is and can be found everywhere.

Dan

Except on the west coast where Fir reigns supreme. All we have out here are 1x's in pine.

[pauldub]

I used Doug Fir when I rebuilt the front and back of my TT some years ago. Doug Fir is stronger and more decay resistant than most of the softwoods. I saw Doug Fir studs at Home Depot in Chicago a week ago and that's a pretty long way from where it was grown.

[Hammerboy]

Go to the lumberyard and ask for #2 pine 2x whatever,rip it to size, (you need a table saw anyway 😉 that's all it is and can be found everywhere.

Dan

[goducks10]

Northwood MFG (Nash) and Jayco (Jay Flight) each make a wood framed TT with fiberglass sides. That wood (pun) seem to make it stronger than the old school corrugated aluminum. Not sure on the wood type though.

[BobsYourUncle]

All the ones I've torn apart or repaired over the years have been constructed with KD spruce. And when I worked at a trailer factory in the early 70's, we built with spruce.

No fir as it weighs a lot more than spruce. Spruce is strong enough yet a lot lighter than fir. Once it is all fastened together, glued, stapled together etc it makes for a strong lightweight unit.
Fir gets very hard with age and is more prone to splitting with flexing and movement. That's one of the reasons fir is not suitable for RV application.

When they KD (kiln dried) the spruce, the moisture content is largely gone and it does preshrink somewhat, but it is very prone to twisting warping etc. More so than fir. So it's important to buy it straight, store it out of the sunlight and use it ASAP. Once in place in a wall or whatever, it is held in place by the structure it is being used for and will stay there with minimum warping.

But it will fly to pieces in a serious collision or rollover.

[westend]

The few times I've repaired a TT frame, the framing has been typical S-P-F, an inclusive rating of lumber (Spruce, Pine, Fir).

My old Starcraft has 1" x 2" (nominal) studs. Actual dimensions are 1 1/4" x 1 5/8".

[Bruce_Brown]

I was being a bit tongue-in-cheek in my "it doesn't take much to demolish" answer, to a point. I understand exactly what you're saying; mine was more of a "look how fast they become toothpicks" when they hit something statement. They may hold a light snow load (and where we live 2 feet is a light load), structurally they're not really all that strong.

[Gdetrailer]

Bruce Brown wrote:
^^^ Even leaving the paneling and siding on it doesn't take much effort to demolish a typical wood framed RV.

As far as the type, as has been noted, the cheapest, lightest stuff they can find.

When I rebuilt our TT I went to the local lumber yard and bought 2x2's by the bundle. I glued and screwed everything back together, double and tripled sealed everything, beefed up where I could without adding unnecessary weight and it's held up well.

Actually, RVs are a lot stronger than you would think and that IS because of the paneling creating a structural truss.. Without the paneling there is no way that 2x2s would be able to withstand 1ft to 2ft deep snow loads..

I have seen 2ft+ snow and ice drifts on top of my TT and it has not suffered any structural damage.

Take the paneling and siding off and 6" of snow would easily collapse the framing..

It should also be noted, harder wood does not necessarily make a structure stronger.. Many hardwoods can shatter/break under loads when softer pine species will simply flex..

You DO want some flex or give to the structure otherwise something else will have to give..