grey foam

The Boy Builder says our home has gone from looking like a pirate ship to looking like a castle. The change that has brought this one is the addition of the grey foam.

As weather allows, we've been applying rigid foam insulation to the exterior of our structural framed walls. When all is said and done, our walls — from inside to out — will have the following layers:

:: 1/2 inch drywall and plaster
:: 5-1/2 inch 2x6 stud walls filled with blown in insulation
:: 7/16 inch OSB sheathing
:: 8 inches rigid foam insulation
:: 3/4 inch nailing strips
:: Siding – in some places bamboo plywood and in some places corrugated steel

When you add all that up, our walls will be nearly 16 inches thick! And an approximate insulative value of R-5000, by some accounts.

The process of getting all that foam on the walls goes something like this:

~ The first step is the prep the ledge. Our basement walls have 7 inches of foam on the exterior and this foam serves as the ledge. Before we could get started, we cleaned snow and ice off; cleaned mud, dirt and grit off; fixed any sealing that needed fixing; roughed up the surface with a rasp; and attached metal wire mesh to be folded up over the nailer strips to keep varmint from crawling behind our siding.

~ While the ledge is being prepped, the window openings are cut out to be marked on the foam

~ Next tall "sheets" of foam are raised into place and dry-fitted. Cut-outs for rafter tails, windows, and doors are marked and cut out with a hot wire cutter.

~ Then expanding foam glue is applied to the entire surface of the foam facing the wall, being sure to have a continuous edge and no sneaky circuitous routes for air to get through as well as good adherence to the wall. The ledge is also foam glued.

~ The sheet is then raised into place, being careful not to smear the glue around during raising.

~ During this part, someone else is applying gluey stuff to the backs of the nailing strips.

~ Then there is a frantic period where everyone is climbing around on ladders and scurrying up and down stairs to apply the nailing strips with long screws, clamp the foam to the wall and otherwise make sure the foam gets securely adhered to the wall before the glue sets.

~ Then we do it all over again until the house is complete! When we're all done, maybe we'll get another grin like this:

All this must be done when temperatures and weather conditions allow, meaning that it's been a slow process. And, despite the fact that we are talking about styrofoam here, which isn't theoretically very heavy, it's still serious work getting that foam up. All the slipping and sliding on snow, all the up and down on ladders and stairs, all the holding heaving impact drivers in awkward positions, all the lifting of 8 inches thick 18 foot long 4 foot wide pieces of foam adds up to sore muscles and tired bodies.

But that doesn't stop some Boy Builders from making a little artwork from the materials.

So come on by and check out the castle sometime. Just be careful of the guard. He can be mighty fierce sometimes.