Anatomy of a House: Understanding the Components of your Home (Part 1/3)

You’ve lived in one your whole life, but is the structure of a house still somewhat of a mystery to you? We’ve put together this 3 part series, released weekly, as a simple guide for a crash course in what makes up a house. We’ll stay out of the weeds with details, but rather we’ll focus on a description of the 11 main systems of a single family residence (SFR) and some key things to know about each. Houses are built mostly in the order below, though some components are built in multiple steps due to waiting for other parts of the house to be completed first. This guide is designed for the average homeowner who seeks a base knowledge of what goes on behind those walls in order to empower them to maximize the asset they own.

The systems that make up a house are:

The Structure:
1. Foundation
2. Frame
3. Roof

The Functional
4. Windows/Doors
5. Plumbing
6. Electrical
7. HVAC

The Finishes
8. Siding / Gutter / Soffit / Fasia
9. Drywall & Paint
10. Interior Finish Carpentry
11. Finished Flooring

Today we’ll start with the structural components: Foundation, Framing, and Roof.

1. Foundation

Most houses are held up by cinder blocks under the exterior, perimeter wall of the house. Mortar holds them together and allows them to seat properly to be there a long time. Under the concrete blocks, however, is the footer. The footer is the concrete poured into the ground.

Perhaps you’ve driven by a development just started with a bunch of cement squares in the ground, and about level with the ground. Sort of like a cement, square tube dropped into the ground, the footers have been poured! Once they cure, the block foundation can be stacked on top.

If the house is built in an area with reasonably soft soil (that is, not limestone or rock), the builder will often dig deeper into the earth and pour a concrete slab and build the block foundation up from there to make a basement. Digging less far down with no slab would be a crawl space (see our article about the mass-produced crawl space design flaw here). The third option is a slab pour at roughly ground level. The homeowner then doesn’t have a basement or crawl space (or the maintenance to go with it!).

There are a few things the prudent homeowner should know about the foundation. First and most important: the number one enemy of a solid foundation for decades to come is H2O! Yes, water! Water moves through the ground or across the surface of the ground which can disrupt the setting of the soil the home was built on. Soil moves or becomes saturated with ground water, slowly-but-surely robbing the foundation of its support.

Also, foundation repair is often toted as the big, bad, scary repair. Yes, it can be costly, but fear not! Very, very few houses will ever have serious repairs needed, especially if the homeowner pays attention at all to maintenance. If you see a foundation crack bigger than roughly 1/8 – 1/4″, you definitely have settlement. It may not need repair, just preventative maintenance to stop the bleeding. If it does need repair, one $2000 pier underneath it may do the trick. And that’s with a lifetime guarantee!

A healthy foundation does not have cracks (hairline cracks usually okay), and if you look down the side of the wall from one end, you won’t see it leaning, bowing, or twisting. The most common problem can be found at corners of the foundation.

2. Frame

“They built that house in 2 days!” It’s amazing how fast the wood framing of a house can pop up, isn’t it? It looks like a lot of progress, but it’s just the beginning. It consists of the wood from the foundation, all the way up to the roof rafters and roof decking. The framers will start with laying 2x6s or 2x8s across the foundation walls (on top of the rim joist and various moisture barriers), which become the floor joists. Sheets of plywood lay across the top of these joists, called subfloors. They’ll use 2x4s standing on end to frame the walls, and so forth. Engineers design what size lumber is needed to properly hold the weight of the house. Around the outside of the home, the framers will tack sheathing, mostly sheets of plywood, to the 2x4s.¬†The picture to the right says it best.

The framing seems to hold most of the mystery of a house. Drywall is hung later, entombing the secrets between the 2x4s and other lumber. In here insulation is placed (between wall 2x4s and between ceiling joists in the attic), electrical wiring is run, and plumbing is run. It is also in here that pests or mold will hide.

Things to know: Things don’t go wrong with the frame very often, as symptoms are often visible in other affected parts of the house first. A roof leak can slowly rot out, for example, the 2x4s that are the exterior wall of one corner of your house. But, you would notice rotting siding or wet drywall on the inside first. Sometimes, it is inevitable, however, and parts of the frame must be replaced. Termites love to chew on the floor joists of a home, and they may not be noticed for years until the floor collapses! Framing repairs, will often only be expensive because of the other work that needs to be done after strong lumber is in place, such as replacing the drywall or hardwood floors. Having a qualified tradesman handle any of your framing repairs is important for obvious reasons: This is holding up your house! If he opts for the 2×4 instead of the 2×6, you may not notice the ceiling sagging until years later, and you are back to square one.

3. Roof

The primary job of your roof is to shed water to the gutters, away from the inside of your home. Plywood will be nailed to the top of the house (called decking), and felt rolled out as an extra precaution. Most often, asphalt shingles provide the visual you see from the street in front of the house. There are other kinds of roofs, such as metal, tile, or rubber (flat roofs), and there’s even solar panel shingles (that the owner of Tesla is developing). “Dimensional” or “4D” shingles are currently the preferred standard for roofs. They have a lifetime of 30 years, and only cost perhaps 5% more than 25-year “three-tab” shingles.

Vocab Bonus: Flashing is a term referring to the metal that’s bent to fit around fixtures, corners, edges, etc. Shingles are laid on top of any flashing, but it provides a critical layer of protection around, say, where your chimney meets the roof.

Things to know: Most roof leaks will happen around fixtures, such as a pipe vent boot or around the chimney. When you start to have these types of repairs more often than once a year, your roof is probably on it’s last leg. Before you spend $500 per year on roof repairs, just replace it. An economical option is to lay new shingles on top of the old ones, but many roofers will say this leaves you prone to leaks sooner than usual. It should be noted that the nature of roof leaks causes them to be difficult to perfectly repair. Even top professionals may not be able to get it water-tight. You are buying time until the next roof replacement! Other signs of a roof near its end are shingles missing or curling at the corners of the tabs.

Roof vents seem annoying, but they prolong the life of your roof by letting the summer heat out. Speaking of airflow, the current building standards agree that air should be allowed to flow easily through your attic (under your shingles and decking). Moisture will evaporate and flow out the vents.

If the top ridgeline (the top point where two slopes meet) appears to have a sag, that means your framing has weakened. It could be from age, poor construction quality, or moisture damage. Not necessarily a repair to make, but something to be aware of should other problems arise.

That’s it for Part 1! Stay tuned for more info helping you understand what’s going on behind those walls.

Remember, if you have a house to sell, you can download our How To Sell Your House guide with a couple clicks in the right margin. We would also be glad to answer your inquiry for an offer in 24 hours or recommendation on what you should do.

One thought on “Anatomy of a House: Understanding the Components of your Home (Part 1/3)

  1. tHANK YOU. i AM A NEW HOME INSPECTOR IN THE MAKING. I AM LEARNING ABOUT THE ARIOUS SYSTEMS IN THE HOME. THIS CRASH COURSE MAKES IT EASIER.

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