Hardwood or softwood?

[BrianMacc]

Hello everyone, first post.

What type of wood, hardwood or softwood, do most of you use for cribbing at MVA's.
We use softwood exlusively and i am wondering about it's load bearing capabilities. Any advice?

Thanks, Brian

[Lewiston2Capt]

Actually we use hardwood for our 2X4 and 4X4 cribbing sections and soft wood for our step chocks. We have also tried the plastic cribbing with some success. However in light of the spectacular review it got in this forum I am leary of using it in the winter time. Hope this answers your question.


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Shawn M. Cecula
Captain
Lewiston Fire Co. No. 2

[Rescuespike]

Brian,

All of our 4X4 cribbing is oak, our step blocks and wedges are made out of treated pine. We have specialty cribbing that is made out of maple plywood with steel backing.

Just like my door stops on my helemet, I would prefer to use a soft wood as a wedge or a stepblock. The piece will give alittle before it splinters or cracks.

Chris Schultz
Mountain Ambulance www.rescue70.org

[MetalMedic]

We use soft wood for our cribbing and hard wood for our plates. Our 4x4s and wedges are made from pieces of treated pine that the local lumber yard can't sell for things like decks because they are warped or damaged. Leaves plenty of wood that makes decent cribbing and is inexpensive for us. If stacked properly, we feel it should do the job well as far as weight bearing. The soft wood also takes a "bite" under load so there is less of a chance of a piece "kicking out".

Our step chocks are made from a 2x6 base with 2x4 steps. These are untreated pine and they do show some more wear than the 4x4s do.

Our plates are 2x10 (or maybe 2x8) made from untreated oak. Since the purpose of these is to create a hard surface to work from, the hardwood seemed to be a better choice.

Still waiting on the grant to purchase the plastic stuff... I'm sure I'll be posting my opinions when we get them.

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Richard Nester
Orrville (OH) Fire Dept.


[This message has been edited by MetalMedic (edited November 02, 2000).]

[rmoore]

My personal experience has made me shy away from pressure-treated lumber as cribbing. Most critical in my mind is the problem it presents when wet with water or other fluids.

Due to the treated wood's resistance to moisture, it repels oils, antifreeze, even rain water. When exposed to these fluids at a crash scene, I find that they tend to bead up on the wood's surface. These droplets form beads that remind me of miniature ball bearings. Theses beads of moisture make the cribbing, especially a box crib, very slippery. I don't like that at all.

In the Plano fire department for example, we have purchased cribbing that is hard oak or hard maple and is unfinished lumber. We only paint the ends for identification. We do not use the plastic cribbing except for the one-piece molded stepchocks.

If you utilize plastic 2x4s, 4x4s or plastic wedges, I believe you are working with an inferior type of cribbing material.

When something goes wrong at an incident due to cribbing failure, I believe you are liable. Your department will be hard pressed in court to prove that plastic cribbing works as well as either soft or hard wood does.

Don't take the risk. Go hardwood for everything but stepchocks!

Ron Moore
firehouse.com Forum Moderator

[brothertom]

We use untreated pine for cribbing amterial. Water and oils, as ponted out by another person, tend to bead up on treated lumber and makes the blocks slippery. The soft woods will give a little before they break, especially the wedges. Of course, when you are using untreated lumber, it has to be inspected for rot, et. periodically, but then all fire/rescue equipment should have a regular inspection and maintanence schedule. Tom

[SCCARESCUE]

We use Hardwood for all our cribbing, except stepblocks. Hardwood is readily available to us in this region. We use "rough cut" lumber - it gives a "non-skid" surface to each piece, which helps each block lock onto the next piece. Oil, gas, anitfreeze, etc have no slippery effect on the cribbing. Another advantage of hardrwood is that these fluids do not soak into the wood. Another advantage is that with a rough cut surface, we can trim pieces as we need to with a chain saw and it all looks the same. If the wood becomes broken, unusable or simply un-retrievable, it is very easy and cheap to replace.

Softwood does not have the strength to work under heavy loads or even with sharp edges. Fluids soak into the softwood.

Hardwood is the best for many good reasons!

[CribPac]

Hardwood,softwood,plastic. I have used them all in demanding situations. My company manufactures CribPac cribbing kits and it's mission statement is " To supply the best products to the fire and rescue services". I use bandsaw rough cut Maple. The blocks are then cooked in PEG1000 to help prevent splitting and absorption. I feel step chocks should be expected to take the same loads as the cribbing,so I make them of Maple too. Many departments carry air bags capable of lifting 72 tons for 2". If more lift is needed cribbing will have to hold the load. This is just an example of planning for the worst and hoping for the best. For more information on the mechanical properties of wood,go to my web site <http://www.sover.net/~branch>. go to "Safety and Tech".. "Remember don't lift it if you can't hold it".
Frank Maltese

[Islander]

We use rough lumber (either spruce or fir) for our smaller cribbing, plates and step chaulks.
Just recently scrounged some rough 4" X 4" X 8' birch for blocks and longer (4 ft) cribbing. I think the hardwood should be more durable and will last longer although it is much more expensive (and harder to scrounge).

Around here it seems as if the manufacturers take the worst possible pine lumber and pressure-treat it. The stuff that i've used is too soft, has many defects, can be quite rotten and, like painted board, probably a little slippery to boot.