Glulam

Tags

barn, Custom Design, Frame, shop guys, timber frame

The boys are back from another raising in South Carolina and are getting ready for our next project, a glulam job in Pennsylvania.  We have gotten a lot of requests for glulams lately, and I thought I’d write a blog about this particular building medium.

A project we did in MA for a residence.

Glulams, or glued laminated timbers, are highly engineered beams that are designed with several things in mind.  They can be graded for extremely high stresses or for minimal spans.  This is engineer-speak to me, and relates to how the boards are layed up.  The only thing I can speak knowledgeably about is that if it is a 24F designation it has an allowable bending stress of 2400 psi.

All of this is to say that glulams are really really strong.  Because of how they are constructed they typically only lend themselves to steel joinery, as opposed to traditional mortise and tenon joinery as is typical with heavy timbers.  The choice to use glulams is both an aesthetic and a structural decision:  some people like the look of the individual striations of the laminations and the steel, and the strength of the glulams is measurable and quantifiable.  Engineers love to have actual numbers with which to work.

As far as the look of the glulams goes there are several options that clients have.  First is the species of wood involved.  We have worked with Douglas fir glulams, southern yellow pine glulams, western red cedar glulams, and port orford cedar glulams.

This was a project in WI that looked out over a lake.

Another option is the curve of the glulam.  If there is a sizeable curve in the beam it may be better to use a glulam rather than a beam that is sawn with a bandsaw.  There are a couple of reasons for this:  the beam that is sawn will be by its very nature weaker than a glulam that was designed for that curve and glued with that particular radius.  The other reason is that there is a lot of waste in a beam that is sawn to a curve.

You can see both a curved glulam above and a straight glulam below.

Timber Frame on the Cape

Yesterday I went to Cape Cod to discuss an upcoming Timber Frame project there.  We built a beautiful barn a few years ago, the Osprey Horse Barn, on Martha’s Vineyard.  What a gorgeous frame:

I can tell you that I’d love to live out on the Cape, but where would I keep my chickens?  I don’t think they would be very good on the beach, although they do like some grit in their crop from time to time.

This particular barn opted for a timber frame structure and 2x rafters, which can save a lot of money for the roof system.  Traditional joinery can also be a very cost-effective way of joining the timbers.

 

 

Summer in Vermont

Some people think that summers in New England are cool and breezy but I can tell you that despite our northern latitude we still get plenty of sunshine and heat.  In fact, Vermonters are dropping like flies in the windows as the temperatures creep up towards 90 degrees Fahrenheit.

The pellet stove is obsolete in the summer months.

Even in the shop the warm air reminds us of the usefulness of our sweat glands during a heat spell.

Who needs air conditioning when you’ve got warm Vermonty breezes billowing at you?

The truth is that our passion is cutting timber frames and we’ve got a good crew, both in the shop and in the office, to get the job done regardless of meteorology.

Can I raise my own frame?

Tags

Comealong, Frame, Raise my frame, Timber

We often get asked if a GC or a home owner can raise their own frame after we have fabricated it. The answer is Yes you can. We will test fit the pieces here in our yard or shop to make sure everything fits properly and we will number and name all pieces both on the print and on the individual pieces to make the process as easy as possible for you.

If you get to a point where you are not sure what to do next we encourage people to call and ask questions. We are happy to help. The biggest hurdle in raising your own frame is quite often not having the right tools. Just a few tools you will need are; comealongs (we usually bring about 15), nylon straps, 1/2 inch drill, pull saw, concrete hammer drill, etc. The list is quite extensive. We usually bring an 18′ trailer with one of everything in the shop when we go on a raising. A wise man once said “it’s better to have it and not want it than to want it and not have it.”

How do you turn a timber framer into a salesman?

Tags

adobe, PDF, sales, timber framer

It’s not possible you say? Well, that’s what I thought too, but it happened to me just two short years ago. At that time I

had been working in the shop for about 10 years. I had held every job from laborer to shop foreman and everything in between. We hired a new sales person that we thought would be great. Apparently thought is the key word here. She really couldn’t get a grasp of what we do or the product we sell. One day as the work load was dwindling in the shop I said to the owner ” I could do a better job at selling than she is”. Oops, my mistake. The owner responded with “okay go in the office and start selling” I won’t lie to you, having no background or training in sales I was quite nervous, but hey, I know the product right, so how hard can it be? Well, I can run a 16 inch saw, a chain mortiser, and layout and cut complicated hips and valleys, but when it came to computers I realized I can turn one on but that’s about it. Poor Sandy, Julie, and Jessie, they have had to teach me so much and put up with all of my questions. Sandy, whats a PDF? Do I have Adobe? You mean like a hut? What’s an Adobe? Cut and paste? Won’t that ruin my screen? All right it wasn’t quite that bad but I bet all three of them are glad I finally figured some of this stuff out. Well, here I sit two years later and they haven’t fired me and Sandy still has all of her hair, so I must be doing something right.

Timber Bandsaw

Tags

arches, Bandsaw, mafell, oliver

Above is a picture of Mike cutting a curve in a timber joist. We use a Mafell Z5E hand-held band saw for small curves.

If we need to cut a curve in a larger member we use an Old Oliver Band saw.

This saw is old but it works great and it was made back when they used to make tools to last. It can cut a timber up to 14″ deep.We made a rip fence for it out of a 4′ clamp and some 3/4″ plywood.

 

Dovetailed Joints

Tags

come along, Dovetail, Joinery, timber frame

We use dovetails to secure (almost) all of our joists and purlins. The dovetail pocket is cut about 1/4″ bigger than the dovetail itself.

 

This allows the dovetail to slip in easily when you are setting the joists or purlins and then move on to raising the rest of the frame and come back to tighten the joint later. The geometry of the joint will ensure that it will not slip out while you continue to set other pieces. To tighten the joint the two rafters, or girts, depending on if it is joists or purlins are pulled tight with a come along and nylon straps to prevent any damage to the timbers and then hardwood (usually Maple) shims are driven in between the dovetail and the pocket pulling the joint in tight.

 

You must  be certain that you are ready to tighten that particular joint though as once the shims are put in place it is very hard if not impossible to get them out.

Questions about timber framing?

Tags

information., questions, Timber Framing

Do you have questions about timber framing? Feel free to ask us anything. I have been with VTW for 12 years and have seen many different buildings and designs. We have been in business for 24 years so if I don’t know the answer I’m sure we have the resources to find it for you.

Housed Tenons

Tags

Housing, mortise, tenon, twisted timbers

As most timber frame companies use “green” wood for their frames and not kiln dried wood you often have an issue with the timbers twisting as they dry. In many of our joints we will use a housed tenon

to reduce twisting.

As you can see when the two pieces are locked together

there is very little room for movement. Be sure to ask your chosen timber frame company if they use housed tenons to reduce twisting.

Draw Bore Pegs.

Many Timber Frame companies, including ourselves, use a method called draw bore pegs to get tighter joints in their members.  The draw bore method is basically offsetting the peg hole placement in the mortise and the tenon. For example, the mortise side would be drilled at 1 1/2″ but the tenon side would be drilled at 1 7/16″. Thus, when the peg is driven it draws the joint tighter together. Like anything else in the world there are the people out there that disagree with this method and say it will crack the member on the mortise side or that it will break the tenon, I can see this happening if you use to large an offset, say 1 1/2″ on the mortise side and then an 1 5/16″ on the tenon side, but we have not had a problem with this method in the 24 years we have been in business.