Saturday, April 14, 2012

Sub floors, Exterior Walls, Modern day construction changes to custom home building

Modern Day Construction for custom homes Part 2

In today’s modern world of construction things are changing year to year faster than they did decade to decade in any other previous time period. In this multi part series I will traverse through an entire house starting with the foundation and working my way up to the roof and then to the finishing’s. I will explain what has changed in the last twenty years in custom home building.

One thing that you should be able to take away from this is how important it is to not just hire the right general contractor to build your custom home but how important it is to hire  one that is up on today’s building methods.

Here are some changes that have come along in the last 20 years alone;


Twenty years ago we used solid convention lumber that was either 2x8, 2x10 or 2x12. The spans were limited by the size and strength of the wood. On top of the joists we installed ¾” plywood sometimes glued and nailed down to the joist.

Today we use wood “I” joists. They are an engineered floor joist that is constructed of pieces of wood glued and pressed together, with a 2x material on the top and the bottom. The webbing in between the 2x is made of OSB and can be cut out in large circles to accommodate plumbing and heating pipes. They also help remove the squeaks from the floor and can be spanned longer distances then conventional lumber. Because they are made from other small pieces of wood they do not require the large size of trees that conventional lumber does. The topping for the floor is now an OSB product that is specially made for being exposed to the weather and comes with 120 day weather warranty not to come apart or swell because of moisture. The OSB be is always glued down and then screwed to the joist instead of using nails. This helps eliminate squeaks and movement in the floor.

Exterior Walls:

Exterior walls twenty years ago were all assembled the same way. 2x6 framing, with 7/16” OSB on the outside. Then the house wrap was applied and your exterior finishes attached to that. The inside of the walls were batted with pink insulation and vapour barrier applied over it with acoustical caulking. A lot of times all the framing was done by installing hand nails, hand driven with a hammer.

Today we still use 2x6 framing and 7/16” OSB with house wrap on the outside. But there are a lot of other options that have gained popularity because of their energy efficiency and speed of assembly. These framed walls are put together now with air driven framing nailers that speeds up the framing process 10 fold.

The other popular options for exterior walls are;

ICF (insulated concrete forms) are not just for the basement, they can be used for all the exterior walls. ICF walls are poured in lifts per floor. So you pour the basement first, then the first floor and then the second floor. You frame every floor as you go as a working platform.

Stress skin panels. These are large panels that are premade and measured in a factory for your home and delivered on site. They made of a 6” foam core with a piece of 7/16” OSB glued to each side. You install them with a crane and then cut your windows and doors out later with a chainsaw or reciprocating saw.

Instead of 7/16 OSB on the outside of your 2”x6” walls they install a 1.5” to 2” of polystyrene foam and then you’re finishing is installed on top of it.

When vapour barrier is installed, acoustical caulking is still used, but there is a lot of tuck tape used to give the vapour barrier a better seal, especially around difficult areas and light boxes. Tuck tape is a red adhesive tape that has been engineered to stop air leakage.

After insulation has been installed, you can install a ½” to a 1” layer of foam board that has a reflective surface on one side of it. The foam board is installed on the inside of the wall before the drywall goes on and the reflective foil is placed facing into the house. This helps the insulation value, stops air leakage and reflects the heat from the inside of the house back into the house instead of allowing it to penetrate through the wall and cool with the air from outside.

Look for Part 3 coming soon....

Rob Abbott
Operations Manager
Village Builders Inc.

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