Friday, December 21, 2012

Timber Frame Renovation

Remodels are always interesting to say the least. You never know what is behind a wall or under a floor until you tear into it. The job we are working on now also has an addition to the existing home. To make it even more challenging, the original home is a timber frame design. For those who are not sure what timber frame really means, think of a building with only a skeleton of large vertical posts, horizontal beams and rafters. Think of this 'frame' as a finish detail of the project, to be left uncovered as a strong visual element of the final product.

Timber 'Frame'
Now build another standard stud framed wall and roof outside the 'timbers' to carry the plumbing, electrical and insulation required for a modern residence and you get a feel for this style of building. This 'post and beam' construction goes back many centuries because of it's ability to accommodate the fairly crude framing members demanded by the tools available at the time. The term "barn raising" is appropriate here. With good organization, a weekend work party was often used to assemble a complete frame in one long weekend.

Fall Progress

But enough about timber framing history for now. This post was supposed to be about the challenge of a good remodel/addition. Partly because of our late season start our first priority was to complete any roofing details. In most modern timber frames the visual ceiling is made with 2x6 tongue and groove material nailed on top of the rafter timbers. A frame of 2x rafters is then built up from here. The main purpose of this sub-structure is to hold rigid insulation and provide the base for plywood sheathing, roofing paper and finally the roofing itself. For us this phase meant removing the metal roofing from above the two covered porches we were converting to living space and filling the hollow cavities with insulation. Considering the relatively small areas we were working with it was more cost effective to install sheets of 'Thermax' foam insulation (polyisocyanurate) instead of the spray foam used in the original construction. With an insulation value of about R-7 per inch this material rates as high as any material available, in our case allowing an insulating value of about R-38 (a little above code for cathedral ceilings in our area). Once the new insulation was in place we covered the joints with foil tape and sealed the edges and any gaps with spray foam. After reinstalling the plywood sheathing we replaced the outdated tar paper with a self sealing rubberized asphalt material commonly used in our area. The version we are now using (Titanium PSSU-30) has a fine grid embedded in the surface that provides excellent protection as well as a non slip surface durable enough to work on without damage.

Converting Covered Porch
For safety and efficiency, the siding on the second floor walls needed to be installed before the lower level roofing was reinstalled. The existing siding was cedar shingles but the birds, especially wood peckers and flickers, had been having fun destroying portions of it for years.

'Tasty Meal'
After considering many options we settled on replacing existing shingles with a hybrid product based on high quality natural cedar shingles pre-installed on a plywood backing 8 feet long and 7 5/8 inch tall allowing a 7 inch finish cover. Though much more expensive than regular shingles the savings in installation time and the unique construction of the panel itself made the decision easy enough.

Cedar Shingle Panel

In a standard shingle installation the layering of one course of shingles over the next leaves a small gap between adjoining shingles. This gap creates a protected pocket, hidden from view, but accessible to over-wintering insects. Birds can sense this available food source and are more than happy to remove any wood separating them from a very tasty meal. The construction and installation  of these shingle panels eliminates this hidden food storage pocket. I would be surprised if the developers of this labor saving product had bird damage in mind but we are happy to take advantage of this reality. Smarter than the wood. And very nice to look at as well.

Finished End Wall


  1. I can say that when it comes to remodeling, roof could be the toughest part. Before installing the new layers of the roof, you have to make sure that the foundation of the new roof is in good shape. You must further inspect it inside and out. Then do the needed repairs that you found before raising up the new roof. This is the only way to ensure that the roof will provide your home a conducive and comfortable space to live. -Professional Roofing Contractors

  2. The timber wall frames are impressive. The finished end wall also looks great. This looks like a rustic ski lodge. The only thing missing is an image of the finished product.