These may seem obvious to many, but I thought it would be helpful here to describe some of the common materials used in a house.
ConcreteStarting at the bottom, let’s consider concrete in the foundation. It is a plastic material made of Portland cement, a baked and ground limestone named for Portland, England, and mixed in various proportions of cement, sand, aggregate (gravel or crushed stone), and water. Aggregate also can be materials like mica, for lightness in weight of the final product.
Concrete cures (hardens) into a very solid material that is very strong in compression (stress from top to bottom) but not strong in tensile strength (the ability to resist forces trying to tear it apart). To increase ints strength, concrete is poured around reinforcing rods (steel rods with little bumps on them, to promote the gripping power of the concrete). Other reinforcing materials are steel mesh, particularly usable for reinforcing floors and slabs.
Concrete blacks are often mistreated cement blocks (just as concrete is mistreated cement) of cinder blocks. They are made of cement, sand, and water, and are not quite as strong as pouted concrete. Cinder blocks are made from cinders as an aggregate, designed to make them lighter. They are more expensive than concrete blocks and are less water-resistant.
Concrete, by the way, is not waterproof by itself, although it is water-resistant. It is made waterproof by certain additives, increasing its cost, and also by backing it with a vapor barrier like polyethylene plastic sheets or coating it with tar.
If you’re looking to hire someone to do your concrete directly check out our page on Hire a Concrete Subcontractor.
You might think adding this one is a no-brainer because most residential construction is stud framed construction. Or so we think. Yes, wood is common as a building material, but only in places where wood is relatively cheap to grow and mill, and environmental conditions allow it. Tropical, perpetually humid, or native termite areas really aren’t the best places for wood construction. But, for those places that can use wood it’s often in the form of milled, dimensional lumber.
Lumber, when used as the basic frame of a house, includes 2×4’s, 2×6’s, 2×8’s, and 2×10’s, and some planks or beams such as 4×6’s, 6×8’s, etc. They are not full dimension, although they are called dimensional lumber. A 2×4, for instance, is not 2 inches thick and 4 inches wide, but rather 1.5 inches thick and 3.5 inches wide. The reduction is due to dressing (planing) the lumber from a rough (full-sized_ state to its dressed state. Generally in dimensional lumber you can take half an inch off each dimension. The greater the width, the farther away it is from the full dimension, a 2×12, for instance, is 1.5 inches thick, but only 11.25 inches wide.
Other building lumber includes boards, ranging from 1×2’s to 1×12’s. The 1-inch thickness becomes 3/4 inch dressed. The other dimensions are similar to those of dimension lumber.
Tongue and groove boards, used for subfloors and sheathing (the outer wall covering beneath the siding) are reduced even more in width, because the tongue on one edge is included in the dimension, but when installed the tongue is covered. So a 1×6 tongue and groove board is closer to 3/4×5 inches than 3/4×5.5. Tonge and groove boards are also used for paneling and finished flooring, and are called matched boards. When the tongues and grooves are along the sides and the ends as well, the boards are called end-matched. (“Car siding” is a tongue and groove type board, but it’s generally used in finishing applications, like finishing a ceiling or interior walls.)
Lumber is sold by the board foot, which is a piece of wood nominally 1 inch thick and nominally 12 inches long and 12 inches wide. A 1×12 12 inches long is 1 board-foot. a 2×12 12 inches long is 2 board-feet, because of its double thickness. Lumber dealers use formulas to break down the amount of 2x4s and other dimension lumber into board feet.
Highly popular and a real asset in construction is plywood. It comes in many thicknesses, but its dimensions are exact. Most plywood comes in 4×8-foot sheets, although some can be ordered in 10-foot lengths and longer. It is sold by the sheet or square foot.
Plywood is made of several plies of wood, hence its name, laminated together with glue. The term exterior plywood means that its glues are water-resistant. There is no truly waterproof plywood, because wood is not waterproof. The nearest thing to a waterproof plywood is marine plywood. All plywood should be painted it it is exposed to the weather. In construction, it’s best to use an exterior-grade plywood except for fancy trim and other surfaces.
Another wood material with exact dimensions is millwork, or moldings. It is sold by the running for, which is 1 foot long no matter what the other dimensions.
Siding & Roofing
Siding, such as shingles and shakes, is made of white or red cedar and sold by the square, which is 100 square feet.
Roofing shingles are made of felt and asphalt bonded with crushed stone to make them hold together and resist weather better. These are also sold by the square and, as in the case of wood siding, are broken into bindles. Asphalt shingles are graded by weight. A 235-pound shingle weighs 235 pounds per square, installed. Roofing felt, or “tarpaper,” is made of asphalt-impregnated paper or felt and weighs 15 to 45 pounds per square. Roll roofing is made just like asphalt shingles but comes in rolls, and is used on very shallow-pitched roofs.
Drywall or sheetrock is a sheet of plaster bonded on two sides by paper, and comes in various thicknesses and sheet sizes, from 4×8 feet and longer. Water-resistant drywall is used in areas subject to dampness (like the bathroom) or where water is used. But remember, it’s water-resistant, not water-proof.
Several decades ago plastering was a very common way to finish the interior. This is a method of spreading a plaster mix over lath (think old Victorian houses) or a drywall type sheeting. It requires a high degree of skill to finish off a plastered wall to a smooth surface, adding a cost to construction few people want to add to their home now days. Today, putting up interior walls quickly with drywall, taping and mudding is far more common. Although you’ll still find opinions on both sides of the bench for and against plastering.
(Image of concrete footing pour from US Forest Service Flickr page.)