How To Build House and Home                                      

An Information and Instructional Guide

Chapter 10 – Basic Construction

We are finally ready to start the actual construction. This chapter will outline the basic components of the first phase of a wood frame house. We will start with the excavating and end with the framing

Excavating
The property will need to be cleared of all the trees, boulders other items that will not be a part of the final landscape. Use the survey and house design to be sure you are digging in the right spot for the layout of the house.

You should dig down and get a soil sample to be sure it is right for building and whether or not is needs for reinforcements. Common soil components are boulders, gravel, sand, silt, clay, loam, peat, adobe and till. The later two being more regionally specific. The soil needs to be good for both bearing and absorption. Additional fill can be brought in to correct deficiencies.

• Boulders (large rocks) should be removed.
• Gravel (small rocks and rock fragments) is good for both bearing and absorption.
• Sand in generally also good for both. Just be sure there is more than just a thin layer and that it is not too fine.
• Silt is not very good at bearing but does have some weight support ability; it is poor at absorption.
• Clay is good at bearing, but poor in absorption.
• Loam has some capabilities in both areas. Loam is a mixture of sand, silt and clay. Its composition can be dominated by one of three materials.
• Peat is made up of partially decomposed vegetable tissue and is not good for either.
• Adobe is also poor for both, but is used in the southwest US because of its thermal insulating capabilities.
• Till is left from glacial deposits of the rocks, sand, silt and clay, If still compacted it will be good for bearing. It has good absorption capability.

If a well or septic system is needed now is the time to get it dug out.

• The well needs to be located a minimum distance away.
• It needs to be accessible for the large tuck used
• Picking a good spot can be tricky, as not all spots will work.
• Once the well has been dug the water should be tested
• A sump pump should be installed in the foundation floor when necessary. The septic disposal system line or the sewer line should be located below the basement floor.
• Trenches will be dug to lay the pipes from the house. These connect to another trench into which the collection tank is laid. Another trench is then dug from the tank to the septic field where the solid waste will eventually leach out

Before digging you should call you local utility company. They will come in and stake out where the lines exist. They are willing to cooperate to prevent accidents.

Marking the trees you want saved is good idea. Don’t leave it up to a subcontractor to remember

Brush, shrubs and trees will need to be cleared away

The excavation must go deep enough to reach good soil.

After the land is cleared it must be graded. Grading is done in two stages,

• Rough grading redistributes the dirt on a lot to create level ground.
• Finish grading contours the yard to look good and moves water away from the house.                                                                                                                                                                                                                            

Footings
Footings are the base on which houses sit. They distribute the weight of the house onto the bearing soil. The foundations are placed on them.

• Their size is determined by the bearing capacity of the ground on which it sits and the weight of the load being carried.
• Firmer compact soil will make a better base than loose silt or peat.
• Avoid tree-rooting systems and remove any large tree rots that remain in the way. Eventually they will decompose and create space that the surrounding soil will sink into and thus cause cracks in the foundation.
• The most common material footings are made is ordinary concrete.
• Sometimes steel reinforcing bars are added in for extra strength.
• For those houses in colder climates the footings should go down below the frost line.
• Freshly poured concrete should be protected from rain until it hardens. By the next morning it should be watered to enhance the hydration of the cement, which significantly increases the strength and water tightness. This is called Curing. The concrete should be cured for seven days. This is especially important in hot weather since the moisture evaporates quickly and prevents proper hydration.
• Footings should be left for a few days to harden before the foundation is laid.
• Isolated footings are used to support intermediate weights of the house with the basement area. They are poured below the concrete of the basement. Most are 24 inches square and 12 inches high
• Piers are used to support small outdoor loads such as porches and decks. They look and function as short columns.

There are three different types of foundations:

• Slabs – a slab on grade foundation is a flat concrete floor poured directly on the soil with no crawl space or basement. There is also a perimeter concrete wall or footing. They are simpler and les expensive. They cannot accommodate a basement and cannot support more than one story. All inserts (water/sewage pipes, etc) must in place before the pouring.
• Crawl Spaces – here is a space between the foundation floor and the first floor of the house just big enough to crawl around in. The minimum clear height is 18 inches. They are unheated, do not require drainpipes, Floors re typically fill instead of poured concrete and do not need to be reinforced if the walls are concrete or cinderblock.
• Full Basement – Basements can extend under the entire first floor or just part of it. The ceilings range from 7-9 feet high Basements are more common in colder regions because the climate requires the foundation be dug below the frost line.

There are many different types of materials used. The four most common are:

• Concrete Block – it is strong, versatile and readily available. They are easy to use it hard to reach places and complex foundations. They are finished with a thin layer of mortar applied to the exterior walls. Note that block foundations are not good for earthquake prone areas.
• Poured Concrete – This is widely used by subdivision builders as it is quicker and less expensive for multiple foundations (this may not hold true for a single home). The forms are built to the desired height and the concrete is poured into forms (reinforcing bars are added where required). In general they are stronger and resist water seepage better. Thus are also more expensive. Thickness varies with design, but should be no less than eight inches.
• Insulated Concrete Forms (I.C.F.) – They are hollow polystyrene blocks or panels connected with injection molded plastic connectors that accommodate reinforcing steel known as rebars. (Think of Legos). The blocks are stacked to form a foundation and the concrete is poured into them. The blocks are left in place. This system can also be used for the upper walls of the house.
• Preserved Wood (PFW) – A PWF is an engineered load-bearing wood-frame system designed as a foundation for light-frame construction (single family homes, room additions etc.). They are built with a special grade of pressure treated dimensional lumber and plywood. With insulation installed in the stud wall cavities, they can save energy and heating costs. They are easy to finish and more economical to convert to livable space.

To finish the foundation you need to:

• Waterproof the foundation to prevent water damage.
• Install Drainpipes underground sewage and water pipes.
• Prevent termites by removing all woody debris, keep the soil under the house as dry as possible, patch all cracks in the foundation, make sure no part of the wood framing is touching the soil, build the sill plate of pressure treated wood or install a continuous metal shield on top of the foundation wall.
• Backfill (after completing the above steps). The leftover dirt is spread back in and tamped down.

Framing
The structure of a house is found in the framework. It is to the house what a skeleton is to the human body. It is the supporting structure and consists of many parts held together. There are three basic parts to framing: walls, floors and roofs.

Walls:
Three basic methods of wall framing:

• Platform framing is the most common. Its main advantage is that the floor is assembled independently and provides a working surface from which to assemble and erect walls and partitions for the next floor. The sill above the foundation wall consists of a sill and a header. The frame is built one story at a time. The studs of each story end at the bottom of the top plates.
• Balloon Framing is an integrated system where the perimeter walls are erected prior to floor constructions. Floor joists are supported on ribbons let into the walls of the building. It starts by applying a sill sealer and a sill on the top of foundation walls. The sill is then fastened to the foundation walls by the anchor bolts. The studs rest directly on the sill.
• Post and Beam framing is the assembly of framing members that are set at a spacing that exceeds two feet. Pre-manufactured infill wall panels (SIPs) are often used to complete the wall assembly.  The floors and ceiling rest on large beams that are supported by large posts. The posts are spaced far apart to provide flexibility in arranging the interior of the house.

There are two types of walls:

• Load bearing walls carry the weight of the upper floors ceilings and roof and transfer that load through the foundation walls to the footings. Exterior walls and some interior alls are load bearing. Exterior walls also control the movement of heat, moisture and air into and out of the building.
• Interior partition walls usually 2x4) are non-load bearing and are used to divide up the interior space to form rooms and 2x6 wall to accommodate mechanical, electrical and plumbing runs. Steel studs are a common choice for partition and basement furring walls.

To finish the wall framing you need to:

• Plan for openings including doors & windows as well as sink drains, water lines, gas lines vents, doorbells, phone lines and heating and cooling ducts.
• Install the exterior sheathing. Typically it consists of the following materials: plywood particleboard, insulating fiberboard, rigid foam insulating sheathing and styrofoam insulating sheathing

Floors
Floor framing for residential dwellings must be designed and built to fulfill several functions. According to the building code they must transfer loads to the buildings’ structural elements, resist deflection and excessive vibration and provide an acceptable surface for finished flooring materials. As a rule the sills, girders, floor joists and subflooring are the first members of the wood framed structure placed on the foundation walls. These are followed by the outside wall studding and corner posts. Then the interior walls, (the second story if any) and then the roof.

• A subfloor is built below the finished floor and on top of the foundation. A subfloor is not always required for a foundation, but is necessary if the house has a basement.
• The sill or sill plate is the timber (usually made of 2x10 foot wood planks) that’s secured to the top of the foundation wall to form a link between the foundation and the home’s upper structure.
• Support beams or girders are horizontal wood planks that that rest either on pockets in the foundation or on concrete blocks. The top surface of the beam must be level with the top surface of the foundation wall. Vertical posts support the beams throughout the interior of the house.
• Floor joists are horizontal structural planks placed on edge against a house’s sill plate lined p to distributed the weight of the wood framing to girders and sill and to provide a base for floor decking. Joist ends rest both on the sill plates and on interior beams. Joists are placed every 12 –16 inches on center and are made on planks a minimum of 2x10 inches. Planks running around outside wall perimeters that the floor joists are fastened to are called Headers.
• First floor platforms (subfloors) cover the floor joists. They are made of different materials including plywood, hardwood boards and particleboard.

Roofs
There are six basic styles of roofs: gabel, gambrel, mansard, flat, hip and shed. The first three are the most widely used. Typically a combination is used.

The two basic types of roof framing consist of stick-built roofs and roof trusses.

1. Roof trusses are very sturdy for there size and weight. In most home designs roof trusses require no load-bearing walls between the exterior walls which provides more flexibility in designing the interior walls. Roof trusses are also cheaper.  Their biggest disadvantage is the lack of attic space   as a result of the cross members.
2. Stick-built roofs are more appropriate for high pitches or odd-shaped or contemporary rooflines. They use individually erected rafters, ridge boards, ceiling joists and collar beams assembled on the job.

The pitch of a roof will affect several items:

• Higher pitched roofs will shed water and snow better which leaves less chance for moisture to get in.
• Lower pitched roofs are cheaper to construct, allow for easier maintenance and provide more open interior space.

The roof deck is what gets fastened to the exterior of the rafters and to the finished roofing. Most roof sheathing is done with plywood. Roofing felt paper is usually placed on top of the plywood. The shingles are place on top of the paper. Types of shingles include:

• Asphalt Shingles
• Fiberglass Shingles
• Wood Shakes Shingles
• Slate Shingles
• Tile Shingles
• Metal Shingles
  
  Various vents, soffits, fans and a chimney will need to be allotted for. Gutters and downspouts will need to be attached.

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