Preparing to Build the Farmhouse

Over the past year, we have been laying the groundwork – so to speak – to start building the farmhouse. Our County building inspector has actually handled straw bale construction before and recommended a book for us; I picked up a copy and then loaned it to the structural engineer who drew up the building plans.

Last summer, we dug the irrigation pond and used a fair portion of the dirt we removed to build up our building site. According to local statements, many years ago, the ground from the main highway up through our northern neighbor’s property all belonged to the same person, and he had the entire stretch graded for flood irrigation. The grading was roughly 1 foot drop for every 30-40 feet of distance. From the highest corner to the lowest of the building pad (about 70 feet), it dropped over 2 feet. We had to do a lot of build-up on that corner!

Building pad with the tractor sitting on it.
Building up the pad site for the house. The four T posts are approximated corners of the house. For reference: the log round on the right-hand side is about 16″ tall.

Although several online sources and a couple of contractors we spoke to last summer recommended using a vibrating plate compactor, we were not satisfied with the level of compaction that provided, nor was the contractor that we had tentatively engaged to do the foundation and floor pour. Instead, we drove the tractor back and forth, both in the north-south direction and the east-west direction. This gave us much better compaction on the fill we brought in (enough so that it’s actually caused us some trouble now!). The contractor also pointed out that, with a monolithic pour (where the foundation and floor are poured as a single unit), the weight of the concrete would be too much for wooden forms, and he recommended building the pad site out an additional 3 to 5 feet, so that the foundation could be trenched in rather than using a form.

We’ve spent most of this spring trying to get a contractor to do the work on the foundation and floor. Our original contractor backed out unexpectedly. With the construction boom this year, all of the other contractors who were actually willing to consider doing the job quoted us nearly double what the original contractor quoted (which may have had something to do with why he backed out).

Our main reason for wanting a contractor is to do the actual concrete pour. We have done enough construction of our own over the years that we know the fundamentals, and we can do a lot of the work ourselves. However, creating a finished floor takes more finesse and better skills than we have, which is the primary reason we want a contractor.

As a result of the excessive bids for doing the job (which included trenching the foundation, placing rebar and insulation, etc.), we have decided to do the prep work ourselves. Two weekends ago, we put up batter boards and ran string lines, and then started digging on the northwest corner (the one we had to put the most fill on). We used water-filled clear nylon tubing to level the batter boards; we had too much trouble trying to set a level spot in the center of the pad for the laser level.

Batter boards with string line.
Batter boards on the northeast corner. The boards have to be perfectly level. Then you put a screw in the top edge to tie your string line to. After you set all of the strings, you measure where the strings cross: front-back, left-right, and diagonal. You can put additional screws in the boards in order to adjust the placement of the strings, allowing you to create a perfect – or nearly perfect (we’re within 0.02 inches) – positioning for the edge of the foundation.

It took about an hour and a half to dig 5′ of the foundation, and there’s almost 200′ total: we very quickly figured out that digging the 30″ deep foundation by hand was going to take a very long time! We have decided to rent an excavator to do most of the remaining trench work. We’ll still have to do some work with the shovels, because an excavator can’t do really square corners or make a nice, smooth bottom, but we’ll be able to do the majority of the heavy lifting with the excavator.

Foundation trench under string lines.
The section of trench we dug in the northwest corner. Partly, this was a test to see how well-compacted our building site is. We encountered very little sloughing off the sides while we dug this and were able to create a smooth-sided and -bottomed trench, which will have 2″ of gravel put in the bottom before the concrete is poured.

The other part we dug by hand is where the sewer line, which we had installed when we did the sewer line to the trailer, comes into the house. Local regulations require that the top of the main sewer line be a minimum of 12″ below the ground surface, and due to the slope of the land, we could only position the shallow end – where it goes into the house – about 35′ from the septic tank. That means that the main line will actually have to go through the foundation, and we did not want to hit that line with the excavator, so we dug out around it. When we installed the sewer line, we put a T post near the end cap so that we knew where it was at, which made locating it to dig the foundation trench a breeze!

Last week, we reached out to the engineer with some questions about the lumber. We have a sawmill from my dad’s days with the gold and silver mines (for cutting timbers for a mine shaft) and have often cut our own lumber for other projects. The engineering plans recommend douglas-fir lumber, which is difficult to find, and with lumber prices tripling, or even quadrupling, over the last year, buying lumber is a painful prospect. However, we have ample lodgepole pine in our area, so we asked the engineer if that would be acceptable. He was able to confirm that it would be a suitable substitute, and we were able to purchase enough trees from the U.S. Forest Service to likely cut all of the lumber we will need that doesn’t have specific structural engineering requirements (such as the sill plate of the walls, which need to be pressure-treated, and the roof joists that need to be professionally constructed). We paid about $200 for all of the trees (plus, of course, our time to cut, haul, and mill them); right now, we couldn’t buy enough lumber for $200 to frame up even a single wall!

We’re starting to cut the boards that we’ll need for the concrete forms around the top of the pour. The concrete floor is 4″ thick and, of course, sits above the grade of the ground. At the edges, the concrete needs to be 6″ above the surrounding ground after the grading is finished, so the upper 4-6″ needs to be held with forms. We’ll put boards in to make that form, and pack dirt up on the outside to reinforce the wood for the pour; after the concrete has cured, we can remove the dirt and forms to meet the 6″ above-grade requirement.

Our next task, which we did last night, was locating the points where the sewer line comes up through the floor, namely for the toilet, the tub and bathroom sink line, and the kitchen line. Because of the nature of a monolithic pour, we want to keep as much of the plumbing above the floor as we can. Any plumbing under the floor cannot be moved for future remodels, or easily repaired. We’ll get the rototiller out to start softening up the pad so we can dig for those lines. We’ll have to put the plumbing in and get it inspected by the State before we can pour the concrete.

Stakes showing plumbing positioning, with overlay of approximate pipe locations.
We have drawn up the entire house using MasterCam so that we have a 3D rendering. It has helped immensely with being able to figure out where to place things like the plumbing. The bathroom sink is about halfway between the toile and the tub; because it’s on the line going to the tub, we didn’t stake out its exact position.

We also still need to mark where the load-bearing interior walls are, because those need a thicker foundation than the rest of the floor, and we will use the rototiller to prep those.

Yesterday, we picked up the rebar and insulation that we need. We are planning to rent the excavator next weekend, after summer class is over, and hope to be ready to pour the concrete sometime in August. We have already contacted a pump truck (regular concrete trucks can only pump concrete out to 18′, which is only a third of the width or length of the house, so we’re going to need one to reach the entire foundation) and he knows someone who may be willing to do the pour. We have to keep an eye on concrete, as well, because they are currently rationing the amount that concrete companies receive each month. So far, the local companies we’ve talked to have said that hasn’t been a problem, but by the time we’re ready, it may mean that we have to try to get the concrete poured on the first of the month.

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