Some degree of framing is required for every house
There are different methods of wood framing. Balloon framing is rarely used today. We will not enter into detail, but the link is provided if you are interested. Post and beam construction is another alternative not often used in residential buildings. The method of choice for most residential projects today is platform framing.
Framing is a large subject and I will have to rely on links a great deal. I am including the best and easiest to understand that I could find. I may add more in the future if I accidently hit on good ones. Please Note: I do not link to commercial sites except in rare cases. The links provide valuable information or graphics. They are primarily to info sources or other blogs.
Doing your own framing is not terribly difficult, but if you do not have experience there are many places to go wrong. Consider hiring an experienced carpenter to help. This is particularily true if your house is complicated in any way.
Wood is commonly used for framing material in residential construction.
Wood is easily cut and fastened with ordinary tools. Strong and somewhat flexible, a wood frame house stands up well to many of the forces that may act upon it. Wood’s strength is not compromised by heat or cold. Although flammable, proper construction limits the risk from fire. If wood sheathing is used in the form of plywood or OSB, it becomes an integral part of the frame by acting as bracing. Wood is available in different grades suitable for different puposes.
Steel is sometimes used in interior walls for studs, bracing or beams. It is not flammable except at extreme temperatures and high levels of oxygen. Steel beams are very strong, and are used where long spans are desirable. Steel reinforcement is often used to achieve greater wind or siesmic resistance. If angle bracing is necessary, steel is a good choice for ease and speed. Steel interior studs can make walls that are truer and easier to finish.
Using steel studs— The Family Handyman
The strength of steel decreases rapidly when heat is applied. For this reason, it is not a good choice for bearing walls in a house, as a structure may collapse quickly in a fire. Steel is also an excellent conductor, and it can create an undesirable thermal bridge if used in outside walls.
Even if the exterior walls are of a material that does not require framing, the interior walls, roof and ceiling will still need a framing system. Most builders today will use roof trusses. These provide the framing for both the ceiling and roof. No interior bearing walls will be necessary unless the structure is unusually complicated. Trusses are usually manufactured in a factory setting, so there is no point in going into detail on their framing. Trusses will need lateral bracing near the bottom or ceiling chord.
For this article, we are dealing primarily with wood framing.
Other types of walls such as straw bale construction require some framing as well, but I have no experience. I will try to provide a link or two though. Some other types that require little framing are concrete, concrete block, log, or SIP (Structural Insulated Panel) walls.
Wood frame exterior walls in hot or cold regions are usually 2 x 6 construction to allow for more insulation. In moderate climates, 2 x 4 construction is adequate. 2 X 4 is used for interior walls, except where extra cavity space is needed for plumbing or ventilation. For metric conversions on nominal lumber sizes use this link.
Floor framing may be with dimension lumber, or with engineered members such as trusses.
Engineered wood floor joists can speed construction and allow for longer spans. They are economical in many situations, and can compare in final cost to conventional solid wood floor framing. Floor trusses can allow even longer clear spans. Floor trusses are constucted similarly to roof trusses. Steel cross members are sometimes used. Both are worth considering for uniformity and dimensional stability.
Floor joists need to be firmed up against twisting done by installing bridging or by furring strips attached to the underside. Bridging can be steel or wood cross braces, or they can be solid wood. The second joist from the end should be laddered with the end joist. Framing a floor.
Openings for stairs need a double joist on either side and double cross joists at either end. Double stair openings should have further support underneath.
Floor joists are usually sheathed with 3/4 inch tongue and groove plywood or OSB. (Oriented Strand Board). Gluing and nailing is my favorite attachment method. Use a bead of construction adhesive on each joist. Nail with an air nailer loaded with nails specifically designed for floors, or use spiral nails.
Most walls are built laying flat on the floor platform, then lifted into place. They consist of studs placed 16 inches apart with a plate on the bottom and top. 24 inch spacing may be used for stud but does not provide as much support for interior drywall. A second plate is usually added to the top after the wall is raised. This is so trusses do not need to be placed directly over a stud and to tie the walls together
If plywood or OSB is used for sheathing, no further bracing should be needed in the exterior walls. Temporary interior bracing will be needed until the roof trusses are secured and interior sheathing is complete. If foam board or gypsum board is used for exterior sheathing, steel or wood bracing will be needed. If boards are used for some reason, they should be applied on an 45 degree angle. It has been many years since I have seen that done, but occasionally some one may saw their own lumber, and may not want to use more modern materials.
Said the stud to the drywall “I shouldn’t be in here. I’m innocent. I was framed.” Said the drywall “Quit complaining, you were nailed fair and square.”
Openings for doors and windows need headers and special framing techniques Provisions needs to be made for corners, and where interior walls meet exteriors. These are easiest explained with diagrams. Follow the link for a good explanation. There is more than one acceptable method.
Always consider the crown on the dimension wood (studs, plates and joists) when framing. Face all the crowns up on floor joists. They will sag to near level. If a few are extra high, you may have to plane them a bit. It is easier to nail a wall frame together if you keep the crowns up as they are laying on the floor, they won’t be rocking on you. Keep your straightest studs for kitchens and bathrooms where you have to hang cabinets. If you have an obviously bent stud in an interior wall you may be able to straighten it by cutting a saw kerf partly through it and scabbing a scrap piece alongside. When nailing on a top plate, place the crown opposite to the one underneath. You should be able to pull them straight if you work from one end.
You can save time by checking crowns ahead of time and marking with a v. Fasten the 2 bys with 3.5 inch coated nails or 3.25 with an air nailer. Length of nails for sheathing will depend on the thickness. 2 to 2.5 inch should be good, and spiral or ring nails are a good idea for sheathing, especially for the roof. Check your local codes for sizes and minimum spacings. I always put in a few extra to make up for unnoticed misses. It is sometimes hard to tell if you have hit the stud when using a nailing gun.
Caulk along the bottom plate after standing the wall. It would be better to caulk underneath, but this could make things slippery and dangerous when you stand the wall.
You can add a lot of strength against uplift if your sheathing laps over the rim joists and the top plate. If you feel this is too difficult, then use steel ties to hold things together. In some areas, this might be required by code anyway. I think steel hurricane ties should be used for trusses no matter where you are, and whether required by code or not.
Steel ties require special nails.
When laying out walls, always work from the same corner, so you will know where to find studs later, usually from left to right.
Blocking is required if a wall is over 8 feet in height.
If you are building on a slab, the bottom plate should be treated wood. A sill gasket should be added, or caulking should be applied beneath.
Framing a preserved wood basement or stem wall is not much different from framing the rest of the house. Extra ties may be required at windows. Blocking will also be required. Definitely check codes and manufacturers recommendations.
You should consider advanced framing techniques. By using some or all of them, you can save considerable material. These methods also make a house easier to insulate well, with less thermal bridging.
Building stairs is also part of the framing if, you are building on a basement, or have more than one story. Most houses will have at least a few steps that need to be built. Building stairs is the subject for a whole article in itself, so I am just going to include a few links on the subject. Alternately you can purchase stairs ready made, or ready to assemble.
Stairs: the next level by Skip Thomsen
Details for conventional wood frame construction–American Wood Council
Construction glossary–Home Building Manual