TECHNICAL STANDARDS - Page 1 of 2
Framing - Walls and Floors
* In addition to gluing subfloors (with construction adhesive made for subfloor application) and nailing them to the joists with at least the frequency specified by the Building Code, screwing down the subfloor (sometime prior to the finish flooring installation) can improve the resistance to squeaks and vibration. Looking at the floor framing from below, you should be able to see some glue squeeze-out that has dripped from the top of the joists during subfloor installation. I note that despite their manufacturers’ advertising, I-beam-style floor joists do not necessarily produce a squeak-free floor; they are as dependant on proper installation as other products.
* 2x6 wall construction - rather than 2x4 walls - is best to allow for deeper thermal insulation. Wall framing with the studs set at 16" O.C. (On-Center, meaning the distance from one edge over to the corresponding edge of the next stud) is preferable to 24” O.C. spacing (which is allowed by Code) because the wider spacing often results in some waviness of the wall surfaces inside and out).
* Minimum 2x10 floor joists for stiffening floors spanning over 12', or I-joists that don't approach their allowable spans. Manufacturers of I-joist sometimes list their maximum allowable spans along with their recommended lower span limits. Again, the Building Code sets out the minimum standards, not the better quality standards to build by.
* Wooden bridging does help stiffen floors, either solid or as cross bracing, or metal bridging where the two sides do not touch.
Framing – Roof
* 5/8" plywood sheathing (or Advantech or equivalent), even though 3/8" is permitted under the building code, and 1/2" is often used. OSB (oriented strand board) is also used as roof sheathing, but its application as roof sheathing is controversial.
Roofing – Since the vast majority of roofs here are covered with asphalt shingles, this discussion will apply only to that type of roof. Properly waterproofing a roof is challenging; when done thoroughly you should not have any problems with water entering your house due to normal blowing rain or backups from ice damming. The main concerns are:
* Install the shingles following the manufacturer’s instructions! It’s surprising how many roofing installers are not familiar with them. Instructions get quite specific about nail placement, and more. In most cases they also call for a roof underlayment to be installed (to serve as the secondary waterproofing barrier; the
* Install the shingles following the manufacturer’s instructions! It’s surprising how many roofing installers are not familiar with them. Instructions get quite specific about nail placement, and more. In most cases they also call for a roof underlayment to be installed (to serve as the secondary waterproofing barrier; the shingles being the primary barrier.)
* Have a bituminous membrane installed such as Ice and Water Shield or Weather Watch as the roof underlayment continuously along eaves and valleys at a minimum. It should be at least 3' wide, and much better installed almost 6’ wide, as 2 overlapping courses, along eaves, above skylights, and any other areas more likely to have ice dams. It is best to also install the membrane around all sides of skylights, and at intersections where any lower roof butts into a wall, rather than relying on aluminum flashing alone.
* in most cases the underside of the roof should be ventilated to avoid ice damming. It is required by the Building Code, and by most shingle manufacturers.
* Have metal drip edges installed along the rakes (the sloping sides of a typical roof) as well as along eaves (the low edge of a roof).
Framing - Walls and Floors
* In addition to gluing subfloors (with construction adhesive made for subfloor application) and nailing them to the joists with at least the frequency specified by the Building Code, screwing down the subfloor (sometime prior to the finish flooring installation) can improve the resistance to squeaks and vibration. Looking at the floor framing from below, you should be able to see some glue squeeze-out that has dripped from the top of the joists during subfloor installation. I note that despite their manufacturers’ advertising, I-beam-style floor joists do not necessarily produce a squeak-free floor; they are as dependant on proper installation as other products.
* 2x6 wall construction - rather than 2x4 walls - is best to allow for deeper thermal insulation. Wall framing with the studs set at 16" O.C. (On-Center, meaning the distance from one edge over to the corresponding edge of the next stud) is preferable to 24” O.C. spacing (which is allowed by Code) because the wider spacing often results in some waviness of the wall surfaces inside and out).
* Minimum 2x10 floor joists for stiffening floors spanning over 12', or I-joists that don't approach their allowable spans. Manufacturers of I-joist sometimes list their maximum allowable spans along with their recommended lower span limits. Again, the Building Code sets out the minimum standards, not the better quality standards to build by.
* Wooden bridging does help stiffen floors, either solid or as cross bracing, or metal bridging where the two sides do not touch.
Framing – Roof
* 5/8" plywood sheathing (or Advantech or equivalent), even though 3/8" is permitted under the building code, and 1/2" is often used. OSB (oriented strand board) is also used as roof sheathing, but its application as roof sheathing is controversial.
Roofing – Since the vast majority of roofs here are covered with asphalt shingles, this discussion will apply only to that type of roof. Properly waterproofing a roof is challenging; when done thoroughly you should not have any problems with water entering your house due to normal blowing rain or backups from ice damming. The main concerns are:
* Install the shingles following the manufacturer’s instructions! It’s surprising how many roofing installers are not familiar with them. Instructions get quite specific about nail placement, and more. In most cases they also call for a roof underlayment to be installed (to serve as the secondary waterproofing barrier; the
* Install the shingles following the manufacturer’s instructions! It’s surprising how many roofing installers are not familiar with them. Instructions get quite specific about nail placement, and more. In most cases they also call for a roof underlayment to be installed (to serve as the secondary waterproofing barrier; the shingles being the primary barrier.)
* Have a bituminous membrane installed such as Ice and Water Shield or Weather Watch as the roof underlayment continuously along eaves and valleys at a minimum. It should be at least 3' wide, and much better installed almost 6’ wide, as 2 overlapping courses, along eaves, above skylights, and any other areas more likely to have ice dams. It is best to also install the membrane around all sides of skylights, and at intersections where any lower roof butts into a wall, rather than relying on aluminum flashing alone.
* in most cases the underside of the roof should be ventilated to avoid ice damming. It is required by the Building Code, and by most shingle manufacturers.
* Have metal drip edges installed along the rakes (the sloping sides of a typical roof) as well as along eaves (the low edge of a roof).
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