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The Building or Shed calculator includes many of the basic equations for building a shed, pole barn or other framed building from bottom to top including the footers, foundation, slab, floors, walls/rooms and roof.

**Roofing Functions**:

- Roof Coverage: This computes
*The basic building*the surface area of the roof based on the length, width and pitch. The answers are in area units (e.g. square feet or meters). This also calculates the number of plywood sheets (4x8s) or bundles of shingles (33.3 ft^{2}) needed to cover a roof. - Truss Count: This computes the number of roof trusses needed for a roof based on the width of the roof and the on-center spacing.
- Rafter Length: This computes the length of rafters based on the horizontal length and pitch.
- Rafter Cost: This computes the cost of the rafters in a roof based on the width of the roof, on-center spacing and unit price of rafter boards.
- Sheathing Cost: This computes the cost of plywood or OSB on a roof based on the length, width and pitch of the roof and the unit price of the 4x8s.
- Shingle Cost: This computes the cost of shingles on a roof based on the length, width and pitch of the roof and unit price of a bundle of shingles.

**Framing Functions:**

- Room Wall & Ceiling Area: This computes the surface area of a room including the walls and ceiling based on the dimensions. This is useful for drywall, plaster, paint, primer and wall-paper calculations.
- Room Interior Wall Area: This computes the surface area of the interior walls of a room based on the dimensions.
- Room Stud Count: This computes the number of studs (lumber boards) needed to frame a room based on the dimensions and the on-center spacing.
- Room Stud Cost: This computes the cost of studs (lumber boards) needed to frame a room based on the dimensions, on-center spacing and the unit price of studs.
- Room Plate Count: This computes the number of plate boards needed to frame a room based on the dimensions and whether there are single or double top plates. Double top plates are recommended for all load-bearing walls.
- Room Plate Cost: This computes the cost of plate boards needed to frame a room based on the dimensions and whether there are single or double top plates, and on the unit price of the boards.
- Room Wall-board Count: This computes the number of wall boards needed to cover the interior of a room based on the dimensions of the room and the dimensions of the wall boards (e.g. 4x8 or 4x12). This is useful for drywall or paneling.
- Room Wall-board Cost: This is computes the cost of wall boards needed for a room based on the dimensions of the room and wall boards and the unit price of the wall boards. This is useful for drywall or paneling.
- Wall - Drywall Sheets: This compute the number of drywall boards needed for a wall.
- Wall - Drywall Cost: This computes the cost of drywall boards for a wall.
- Wall - Stud Count: This computes the number of studs needed for a wall, based on the dimensions of the wall and the on center spacing of the joists.
- Wall - Stud Cost: This computes the cost of studs for a wall.
- Floor - Subfloor Sheets: This computes the number of plywood or OSB sheets needed for a floor.
- Floor - Subfloor Cost: This computes the cost of plywood or OSB sheets needed for a floor.
- Floor Joist Count: This computes the number of floor joists needed for a floor based on the floor dimensions and the on center spacing of the joists.
- Floor Joist Cost: This computes the cost of floor joists.
- Plywood Cost: This computes the cost of plywood based on the surface area and unit price of a 4x8.
- Room Volume: This computes the total volume of a room.

**Foundation and Basement Functions:**

- Slab Volume: This computes the volume of concrete needed for a slab in the basement or ground floor.
- Foundation Blocks: This computes the number of blocks needed for a foundation.
- Foundation Poured: This computes the amount of concrete needed in a poured concrete foundation.
- Footer Total Volume: This computes the amount of concrete needed in a footer.

The Building or Shed calculator includes formulas grouped in three TABS (Roof - Frame - Foundation) that roughly correspond to three distinct components and phases in the development of a building.

The **ROOF **tab has equations associated with roofing, including the count and cost of rafters, roofing plywood, and shingles. The shingle equations includes price estimates based on shingle price point observations from national providers like Lowes and Home Depot. The unit prices used here are based on a vCalc data repository of pricing (Shingle Pricing).

The **FRAME **tab has the most equations. These equations include those related to the count and cost of floor joists, sub-floor boards, wall studs, and drywall. For anything above a simple one room structure, you will have to develop your estimates room-by-room. The cost data comes from vCalc's tables (see list below) which come from the nationally advertised prices and are updated approximately every two months.

Starting from the bottom and going up, the **Foundation **equations include calculations for the amount of concrete needed for a footer, and then the amount of materials (concrete or block) needed for the foundation walls. And then finally, the amount of concrete needed to pour a slab in the basement to complete the rough construction. These formulas are are all based on the dimensions of the building. However, the block count estimator is based on standard block sizes in the U.S.

The basic construction of a building is the same for many structures. With few exceptions, a building requires a foundation or peers, a frame and a roof. Many buildings have basements that are below grade or partially below grade and these are typically made of block, poured concrete in forms or stone in order to stand up to exposure to the earth. Foundations are often coated with moisture blocking substances (e.g. tar), and perforated piping is often laid in a gravel bed, outside of the base of the foundation and covered by a silt barrier (paper) to drain water away from the base of the foundation in a french drain. The frame of the house is built on this foundation, and in the modern era, the frame is physically attached (bolted) to the foundation. This last step is widely performed to keep a house on its foundation during earth quakes. The boards that are bolted to the foundation are generally referred to a foundation sill plates and are used to affix (nail, screw or bolt) the deck and joists for the first level of the building frame, to the foundation.

The first part of the wood frame is the deck of the first floor. The deck typically has side boards (skirts) that are vertically placed around the foundation with joists running across the span and nailed into the skirts at the ends or affixed to the skirts via joist hangers. The end of the joists rest on the plate and have a direct conveyance of their load (weight) through the solid plate to the foundation. In some cases, when the span of the basement is too great, a beam is erected mid-span for the joists to convey their load in a third place (both ends and on the beam). The architectural design should account for this. Beams must rest on part of the foundation and/or on post (molly columns) that rest on concrete peers comparable to the footers of the foundation.

The frame of a building can have several floors, multiple rooms and each room can have doorways and windows, not to mention many built-in features (e.g. closets). Between rooms are passages and hallways and between floors are stairs. But the basic framing of walls and floor is consistent in most structures. Between floors you will find decks that are made of joists that are roughly surfaced with sub-flooring. Joists are either strong pieces of lumber like 2x12's or I-joist made of composite materials or even steel. The span of the joists and their separation are greatly dependent on the structural load that they will have to bear, but there are some industry standards (e.g. 16" separation). When the spans of joists over rooms are too great, beams are required. Nonetheless, the framing of the building is primarily composed of the walls (interior and exterior). These walls separate the rooms and carry the load (weight) of the floors and roof above. Walls come in many categories including:

- interior
- exterior
- load bearing
- non-load bearing

It is common that load-bearing walls have a double top board (plate). However, some non-load bearing wall can have a single plate on the top. Interior walls are typically covered with drywall or paneling to enclose things like wiring and plumbing and to provide a surface for fine finishes.

Exterior walls are typically strengthened with structural panels such as plywood, have wind braces (diagonal steel) and are covered by a vapor barrier to keep the difference in moister (outside to inside) from leaching into the housing materials. Exterior walls are also used to attach the outermost surface of the house (brick fascia or siding) to the frame. The exterior surface may be siding or even masonry (brick or stone). In the latter case, attachments are connected to the exterior wall and integrated into the masonry seams (mortar joints) as the exterior facing is laid.

All exterior walls are load bearing, which means they carry more weight than that which is directly above them. The weight they bear includes the load of floors that span open spaces and then rest on the load bearing walls. These walls typically have standard spacing of vertical members (16" centered studs) and doubled top plates to provide strength between the studs. It is important for the architect of the building to methodically transfer the weight of every component of a building through every load bearing component down to the foundation and ensure adequate strength is built into the design and materials to carry the load for the life of the building. This all sounds complicated, but some wonderfully simple buildings exist and are still strong after centuries.

Above the frame of a building is the roof. The attic which is formed by the roof frame on top of the house is typically the location of the greatest layer of thermal insulation such as fiberglass. The roof serves the primary purpose of shielding the frame of the house from the water of rain and snow above and of carrying the load of snow (in some climates) until it melts. Roofs have load bearing structures, either rafters or trusses that convey the weight of the roof to load bearing walls (e.g. outer walls). Plywood or purlins are attached to the surface of the roof frame as a base for the final roofing material. The most common roofing material is the shingle which is nailed in layers on plywood. However, there are numerous other roofing materials from thatch, to tile to standing-seam metal.

Once a building is "under roof", conventional wisdom suggests that the job is half done. For help completing the construction job, consider the following vCalc calculators:

The equations in this calculator are a subset of the equations in the vCalc's construction library and are meant for estimation purposes only.

As always, we are looking for ways to improve vCalc's libraries of equations and encourage the public to provide updates and comments to this wiki to make this a better tool for the general public. The pricing information is gleaned from nationally advertised prices on web sites for lumber providers (e.g. Lowes or Home Depot). Please check your local stores for more accurate pricing and point them to vCalc. vCalc would welcome the national advertisers to publishing their materials pricing directly to our free pricing repositories.