Framing roofs for a house construction plan
Now that we have the walls up in our house construction plan, it’s time to either build a second floor for an upstairs, which is the same as building the first floor, or just put the roof framing in place for a single story home.
Let’s work on the single story home by putting up the rafters.
Rafters and trusses can be made to save money so you don’t need to buy prefabricated roof trusses at the high cost of roofing materials.
They need to be strong and you should be generous with them because of the strength they offer.There are several kinds depending on how you want your roof to look. The most common is the W-Type. It works very well and is easy to assemble.
Roof pitch is measured by how much slope is in a 12” measurement. A carpenter’s square helps to find the angle. If you measure 4” up on the square and 12” over, you have a 4 in 12 pitch, which is really quite flat.
A more common pitch is 6 in 12. That will make a stronger roof and it will shed water faster. Pitches higher than 8 in 12 are usually reserved for special house designs or for areas with very heavy snow and ice loads.
When you build the trusses, you want to make them with only the best lumber. Make sure it is free of knots and cross wood grain.
You can use mending plates, which are metal plates that can be hammered or pressed over the joints, or plywood can also be used. The important thing is to make a strong truss at any cost. Both sides of the truss need to have these plates.
The trusses can be attached to the walls by resting the cross part of the truss called the collar beam onto the top plate of the wall. The dimensions you want to build your trusses depends on the slope of the roof in your house construction plan, but the collar beam needs to be a perfect fit according to the measurement of your walls.
There is a notched fit on top of the wall plate so the truss can extend beyond the wall about 16” to create the eave. Some call this angle cut a bird’s mouth. It helps the truss fit tightly into place before it is nailed. You can fasten the truss by either toe nailing it in place or by using truss fasteners.
Next, let’s frame in the cornices by either making extensions from joists and trusses or by building them separately and attaching them. They will need a special kind of cornice to cover the ends of the trusses.
The cornice is framed in after the wall sheathing is finished, but before the roof sheathing is put on. A ledger is attached to the wall sheathing and runs the distance of the wall. A 2x4 works well for this.
Be sure to give the ledger some stability by nailing into wall studs and not just the sheathing. The lookout is a 2x4 cut to the measurement from the end of the truss to the ledger, then nailed to the truss and to the ledger. The soffit and fascia sheathing can then be applied.
The soffit needs to have vents cut into it, which will be covered by a screen when the soffit sheathing is covered by a metal soffit covering. Ventilation is essential in a good home construction plan. The fascia sheathing is the same as the soffit sheathing; it’s just a plywood strip to cover the end of the trusses.
The picture below shows how to build the cornice as part of the framing before the walls get covered with sheathing. This is a more stable way of making cornices. Either way is just fine. Next, the gable end cornice has to be made. Extending lookouts from the gable end can do this.
Once the gable end cornices are framed in, you can then cover everything in sheathing. That's all there is to the roof and eaves part of the house construction plan.
Just as a note of importance, if you choose to paint your house instead of using siding, you will want a good exterior grade of plywood to prevent swelling. There are some individuals in this day and age that still like to paint exterior surfaces. Painting involves high maintenance and continuous expenses. With the low-cost, high-quality sidings available these days, exterior painting is becoming a has been, but to each their own I say.
top of page
Next, gambrel roofs and dormers
Back to framing main page