Can I Build My Own Foundation?
Yes it is possible for anyone to build a foundation with basic tools. The most complicated piece of equipment necessary is an auger. Other than that you will need basic tools like shovel, wheelbarrow, laser level and string.
What is the Easiest Foundation to Build?
The easiest way to build DIY house foundation is a pier and beam foundation. The pier and beam is the simplest type of foundation for a DIYer to construct. Building pier and beam won’t require an excavator or cement truck. You can build the foundation with basic tools and do most things by hand.
Why Build a Pier and Beam DIY house foundation?
Using pier and beam is a tried and true method that is easy to install and will be durable for a long time. It’s no wonder this was the preferred building method for so long for houses.
Sometimes you are building in an area that doesn’t have the ability to bring in an excavator or cement truck. In the case of a rural cabin you will most likely will only be able to build pier and beam. Pier and beam is a good choice for smaller structures.
Building a Durable DIY House Foundation
If you are building on soils that are expansive like clay you will have the problem of the soil expanding and contracting with wet and dry weather. Pier and beam is a great choice to build on expansive soils because it will be easier to level later when settling inevitable does occur.
Since you are using an auger to drill down 4 feet into the earth you will create a much more durable foundation than the standard 6 inches of depth with a slab on grade.
Easy to Maintain
Over time the pier and beam will be easier to maintain and will offer access to the utilities and mechanicals of the house for servicing. Imagine trying to access a plumbing pipe that has burst under the slab of the house. With pier and beam the electric, plumbing, HVAC and other mechanicals are easily accessible under the house.
Pier and Beam VS Slab Foundation
When building a slab foundation the biggest struggles will be the excavating and the pouring of the cement. To build a slab foundation you will need to rent an excavator and hire a cement truck company to pour for you. When you build a pier and beam their is much less excavation and it can take place with smaller augers that drill holes for the piers.
You will also use less cement because you are filling a much smaller surface area than a slab. The best part since the project doesn’t require as much cement you wont have to hire a cement truck. You can buy bags of cement at home depot and mix it in a wheelbarrow with a shovel.
What is the Cheapest Way to Build a Foundation
The cost to build a pier and beam and a slab on grade are similar. However pier and beam will be cheaper to maintain over the long term. A slab foundation is typically a little cheaper upfront than pier and beam because concrete is very cheap. A pier and beam will require wood which is much more expensive than concrete. The cost of pouring a slab is between $4 and $8 per square foot. In my case building the pier and beam for my home came out to $7.1 dollars per square foot.
How Much Does a Pier and Beam Cost to Build DIY?
I was able to build my pier and beam DIY house foundation for $7.1 per square foot. My building was rather small (200 SqFt) so the cost per square foot may be a bit high, usually economies of scale add up over more square feet. It will be roughly the same range as pouring a slab between $4-$8 per square foot. The difference is you can build the foundation without the need for heavy machinery.
What are the Costs for Building a Pier and Beam Foundation DIY?
| Necessary items to build | 60lb bags of cement | Pier Forms | Rebar | Auger rental | Beams | Floor Joists | Subfloor sheets | Simpson Strong Ties | Misc | Total Cost |
| Number of items | 96 | 16 | 20 | 1 day | 8 | 34 | 10 | 16 | N/A | N/A |
| Costs | $299 | $191 | $147 | $129 | $399 | $909 | $586 | $254 | $121 | $3035 |
For simplicity sake let’s consider a 400 SqFt structure you will need 16, 12” wide piers with 4 foot depth. Each pier requires 6 80Lb bags of cement. That adds up to 96 bags total at a cost of 3.12 per bag for a total cost of $299 just for cement. We also need 16 pier forms at $11.98 each adds up to $191.
If you plan on building bigger than 400 SqFt consider hiring out the concrete pouring to a ready mix truck. The prices vary so get a quote from a local company. It will also be easier as you won’t have to haul tons of cement bags either.
Rebar
You will need 3 pieces of 4ft rebar for each pier. Thats 12ft of rebar per pier. For 16 piers that is 192 linear feet of rebar needed. 10ft long pieces of rebar run $7.37. 20 pieces of rebar will be $147.
Simpson Ties and Beams
Simpson strong ties are $15.92 each and you will need 16 strong ties for 1 in each pier. Thats $254 for the strong ties. 400 SqFt will require 8 beams that are 4”x6” and 12 ft long. Each post is $49.98 for a total cost of $399 for the posts.
Floor Joists
After you put your posts in you will frame a floor joist over it. For 400 SqFt structure you will need 34 floor joist pieces. The joists will be 2x10s that are 12ft long. Each 2×10 board is $26.75 for a total cost of $909 for the floor joists.
Subfloor Sheets
On top of the floor joists sheets of 1/2 inch OSB will form the subfloor of the structure. For a 400 SqFt house you will need 10 4×8 1/2 inch thick OSB sheets. Each sheet costs $58.67 which will be $586 total cost to apply subfloor.
Miscellaneous Costs
I would also add in another $250 for the equipment rental and random things like boxes of nails, spool of wire, bolts and other surprises. This beings us to the cost of $3035 for 400 SqFt. This breaks down to $7.1 per SqFt. I should add these numbers have been calculated using May 2021 lumber prices which are very pricey in the aftermath of Covid-19. I would imagine during any other time when prices are more normal the cost of pier and beam and slab would be nearly identical.
Conclusion: DIY House Foundation
The pier and beam is the easiest DIY house foundation to build. The pier and beam design is durable against heaving and settling. This design will allow you to more easily install plumbing, electrical and mechanicals later.
Next step: How to build a pier and beam foundation DIY
More resources: https://tinyhouseexpedition.com/is-building-a-tiny-house-on-foundation-really-worth-it/