Building Confidence

Volume 17 Issue 5
ISSN 1923-7162

Welcome to Dave's Shop Talk's Home Improvement Newsletter of questions from our members on their construction projects, a Tip of the Month and a home remodeling article, both from our website at

Tip of the Month

When determining the swing of a door, stand outside the room. The door should open into the room. If the hinges are on the right hand side, it is a right hand door, it swings to the right.

And a Bonus Tip:

Clean out air ducts once per year. These are the dryer, bath and kitchen fan ducts, as well as, furnace and HVAC (Heating, Venting, Air Conditioning) ducts.

Ask Dave!

Hi Dave, Just wondering how is the correct way to frame ceiling joists for rafters? Do the joists have to be offset and nailed to each other, or can they butt up to each other? Thanks a lot, Bill

Hi Bill,

Yes, most definitely the ceiling joist can be butted up to each other over a bearing wall. BUT, you need to apply a scab over the two joists at least 2' on each joist - 4' over all, nailed securely to keep the joist from pulling apart when a load is introduced to the roof. This scab is made of the same material as the joists. I nail at least 6 - 3 1/4" nails on each side of the splice.

Depending on the roof span and snow/wind load, the number goes up to 11 nails until trusses are required over large spans and heavy loads. Just think how many nails you have at the ends of the joists - to rafters and to the plate, then use this same number plus 1. Make sure the nails are spread out and alternated with the grain, this depends on the length of scab board, also.


Dave, I am planning to build a covered front porch, which will include building a gabled roof and pouring a small slab of concrete. What I typically see in new construction, is that the porch roof is built first, with temporary supports. Then the porch slab or steps are poured and the permanent support posts are added last. My question, would there be any problem if I pour my slab first, install my finished posts, and build my roof onto those posts?

Hi Jim,

In my opinion, based on the building code, the perimeter foundation wall for a house is built below the frost line. At this time we also include the footings for posts which support roofs, decks, floors, etc. The footings for these posts are set below the frost line and concrete posts extend up to about 8" above grade. Usually, the preferred size of wood post is the 6x6, even for decks.

Then, as you say, the porch slab and concrete stairs are poured in place after the backfill is compacted in place. In a retrofit or renovation, we do the same thing. We excavate for the footings, usually square pads with concrete posts, 8" above grade with a steel post saddle on top. Erect our posts beams and roof, then fill and compact the area for the slab and pour it under the roof. If you live in an area, not influenced by frost, you still need to build a footing or pad to support the weight of the roof structure. This footing or pad should be below the slab for aesthetic reasons and have a short concrete base so the wooden post is not sitting in water.

If you pour the slab first and then put your posts on top, make sure you allow a thicker slab under the post to support the roof. This is called a slab on grade with its perimeter formed thicker. (Our slabs for shed and gazebo plans show this in detail) A post saddle should be embedded into the slab at the time of pouring or drilled in later. The saddle not only holds the bottom of the post secure, it separates the wood from concrete. The concrete base for a typical post is usually about 2' square by 8" deep, under the slab.


Hi Dave, I'm installing a massive 8' 2" tall x 6' 4" wide double entry door, What size header should use, in this case? This will be for new 2 x 6 construction. The ceiling is 10' and this is a load bearing wall. Thanks, James

Hi James,

Here is a drawing of a typical header for a 2x6 wall. Minimum header is double 2x8 for a 6'-4" opening.

Diagram of how to frame a header in a 2x6 wall.

In your case you can do the same thing as in the drawing, but add another plate about 1/4" above the jamb with studs up to the header trim. As shown here:

Diagram of how to frame a header in a 2x6 wall with a smaller opening.

Notice that the cripples come right up under the header and the lower plate comes to the side of the cripple. This is so the cripples support the header directly.

You should have the opening large enough so that there is about 1/4" clearance on all three sides of the jamb between the jamb and framing.


Feature Article of the Month

(taken from our website:

Electrical 1: Electrical Safety

During my years as a carpenter in heavy construction, that is construction of industrial and commercial projects such as mine buildings and machine bases to hospitals and schools, I've experienced first hand the various trades involved in my industry. Most men and women are conscientious tradespeople adept in their particular trade. As a carpenter I worked closely with the various trades and picked up some of their skills and knowledge along the way. I noticed with electricians, in particular, how organized and orderly their work was. Electrical wires were routed along cable ways and into electrical panel boxes in a very neat and orderly fashion. When I had the opportunity to wire my own house I bought a book on the Electrical Code and purchased a permit for homeowners doing their own electrical wiring from my local government department. I used the principles I learned from watching electrical tradesmen and applied it with the electrical code requirements as I read the book. As a backup I hoped the electrical inspector would slap my hand if I made a mistake. I was reprimanded on only one fault, not putting in a large enough electrical breaker and cable to a 60 gallon hot water tank. The book suggested the electrical wiring and breaker for a 40 gallon tank, which was smaller. No problem, I easily changed the electrical breaker and upgraded the electrical wire accordingly. Luckily I had an electrical inspector watching my back.

Safety First, Especially Electrical Safety!

During the construction of this website, I've answered questions on simple electrical wiring problems. I want to make it clear here that those not experienced in the basic principles of electrical wiring of lights, plugs and switches in their home should not attempt it without realizing the consequences that their errors may have. If a fire was caused by your negligence or oversight your house insurance may not cover the damage. If removing the electrical panel cover to change a breaker, even though the main electrical breaker is turned off, the electrical panel is still hot. Handling electricity in the home may cause serious injury, death or a fire.

If you want to do electrical wiring in your home, I strongly recommend purchasing a book on the subject that is up to date with the current electrical codes and taking out a permit, if allowed, from your local jurisdiction. The permit provides a backup in case of error, although don't depend on the inspector finding every error you have made. Some homeowners, to reduce the electricians time and ultimately the cost of labor, make an agreement that the homeowner does the electrical work under the supervision of the electrical contractor. This is another form of backup. Of course, the electrical contractor usually has to be a friend or have the confidence in the homeowner to agree with such a proposal. If you are not willing to learn the electrical codes or do not feel confident in performing this work, by all means hire a professional electrical contractor to do the job for you.

The following articles show the ways of connecting 3 way electrical switches, etc. but by no means advocates changing the electrical wiring in your home without the full knowledge of the electrical codes for your area and the consequences of your causing an accident.

Work Safe!!

Dan and I thank you for your interest and support of our Website. We hope we can help you with your present and future projects.

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(Ask Dave) (About Dave)

Your source for building tips, woodworking & furniture plans, house plans and building advice directly from Dave...

Hi, I'm Dave Osborne. With over 50 years experience as a journeyman carpenter, foreman and contractor in heavy construction I enjoyed working with apprentices and sharing the tricks of the trade that others shared with me. Now I get emails from Members all over the world and we include many of my answers in our Free Monthly Newsletters. Some of my answers include drawings and instructions specific to a project, but may also answer your questions. I use correct construction terminology, so you can confidently inform your building supply dealers or contractors exactly what you need.


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