One of the places where amateurs often, and professionals occasionally, bungle a construction job is on the building procedure or sequence. Certain things have to be completed before other steps in the process are begun. Otherwise there can be heavy difficulties.
An example of this comes to mind quickly. A friend, an amateur, was building a house for his in-laws in Bolinas, California in 1967.1 walked over one day to see how he was doing. He seemed to be doing well, was just finishing up laying the hardwood floor. I didn't see any pipes or water lines coming up through the floor, however, and I asked about this.
"Haven't put them in yet," he said.
"You mean not up through the floor yet, or nothing laid there at all?"
"Nothing at all. I was figuring on doing that last."
"You haven't even dug the ditches under there yet?"
"Because that's the first thing you do after pouring footings. You call that roughing-in the plumbing. You dig your sewer and water ditches and lay the pipe. THEN you do the floor. Otherwise, like now, you have to crawl around on your side or stomach in that little crawl space and try to dig the ditches and lay the pipe that way. This earth around here is what we call hardpan clay, which is why no one's septic tank drains well. That clay is so tough we usually have to use a jack hammer on it. Now there's no room to do that or even to swing a pick."
Several years of roughing-in sewer lines on construction jobs in that county made me shake my head sadly at the thought of his difficulties ahead. I made the mistake then of muttering, "I'm sorry I didn't get over here earlier to see how you were doing," and was rewarded with a look of accusation which haunts me to this day.
So the sequence is important. Here is the suggested building procedure for PSP underground houses:
(1) Build downhill terrace shoring and/or temporary habitation.
(2) Dig hole (using earth to make terraces).
(3) Get approximate floor heights using a line level.
(4) Set corner posts.
(5) Set other posts one at a time.
(6) Notch in and bolt roof girders.
(7) Notch in and spike super beams and roof beams.
(8) Put in French drains, if used.
(9) Rough in plumbing lines, electrical conduits, if used.
(10) Put on roofing boards.
(11) Build walls, cabinets, closets, etc.
(12) Finish roof and Uphill Patio excavation
(13) Put in windows and doors.
(14) Install carpet anchors.
(15) Tamp floor, rough smooth it.
(16) Pour concrete base for toilet, bath or shower.
(17) Install plumbing and lighting fixtures.
(18) Finish floor, lay carpets.
(19) Install stove.
We are going to examine these points one at a time giving the reason for the sequence. We'll also try to explain thoroughly just what it is that you do during each of these steps.
Steps (1) and (2) have been well explained in the preceding pages on excavation. We'll make just one further observation here. Many people, when digging by hand, tend to let the sides of their excavation taper. If your earth is holding well, not caving in or crumbling down, you should avoid this. Your sides should be as vertical as possible. Though it often seems a nuisance, or an extra effort to do this, it actually saves you labor. You can only build as large a house as the floor is wide. Since your posts are going to stand straight up, any tapering back that the earthen wall does represents unused excavation, or work that you have done for nothing. If you try to eliminate the taper when nearly done digging you'll likely find you have to swing a pick. So shave those walls vertical as you dig.
The reason for (3) making your floor level at this step is so that you have a true idea of how deep to sink your posts. On a large house it is entirely possible for one end to be as much as a foot higher than the other when you eyeball it during construction. If you sink your posts under these conditions you are going to have to add a foot of earth later to the low side which would not only negate a foot of your hard digging and raise the floor a foot
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more than you wanted it, but also add up to a foot of earth around the untreated portion of the posts causing rot. A more reasonable alternative would be to excavate a foot from the high side. This however has the disadvantage of exposing treatment within your house where it might possibly smell or where young children may touch or even chew on it. Excavating would also make the post less sturdy. The final possibility would be to leave the floor at a slope beneath your carpet. Doing this will cause you no end of future annoyance. Your house will seem most unprofessionally built. You'll notice it for
sure. All of the hassle can be avoided by leveling the floor at this point.
(4) Set the corner posts. You must set the corner posts first so that they can become guides for the other posts both in height and position.
There are a number of steps to setting a post correctly. First you must dig a hole with a post hole digger (greatly recommended over a shovel) which is wide enough to allow the handle of a shovel to fit around the post on all sides during the tamping process. Next, using a level, you must make sure the posts are vertical, and that they stay vertical during tamping. This involves either continually checking while working, having a friend hold the post, or nailing several boards like legs to the post to support it.
Begin tamping by shoveling dirt back into the hole not more than a fourth or a third of the way up. Turn the shovel upside down and pound that loose earth (tamping) so that it becomes compressed or solid (compaction). Shovel another six to ten inches of earth in and repeat the tamping. Do this until you reach the top. If the earth is very dry you may want to dampen it as dry earth compacts poorly. Tamping is important not only because it keeps the post from wiggling later, but because it also provides resistance which helps to keep the post from sinking from the weight of the building above. Another trick to keep it from sinking is to throw as large a rock as you can into the hole before dropping in the post. Being larger than the diameter of the post the rock will help to disperse the weight. It should also help to keep the end of the post from rotting out.
When all the corner posts are in place you should trim them for height. (Presumably you have used posts which have excess length.) Pick out a post on the lower wall, decide how high you want it to be, mark and trim. Using a line and line level find the same height on the other lower corner post. Mark and trim. Repeat the process for the upper wall.
(5) Set other posts one at a time. Use the corner posts for guides. Do this by running a line from the top and another near the bottom of the corner posts of the same level connecting them. These lines must be on the outside. Your posts will doubtless be of different diameter. If you try to line them up so the inside surfaces are in line, then the shoring itself will undulate from post to post.
To set the middle posts follow this sequence: First run the lower line across. Measure where the posts are to go and drop the line to get it out of the way. Dig the holes remembering that they must extend towards the wall past the line (so that you may get the shovel handle in during the tamping). String both lines and drop a post in one hole. If the hole isn't right pull the post and make corrections. Drop the post in again and line it up so that it almost but not quite touches the two strings. This will give you your forward and back plumb, plus the correct position. Check your right and left plumb with a carpenter's level. Begin backfilling and tamping as outlined above checking for plumb as you work. Repeat the process individually for each of the other posts. Trim using the top line as a marker.
(6) Notch in and bolt girders. We built our houses using two different systems. On the $50 house we ran girders across the top and lower wall posts, connected them with what we called "super beams" then notched in our roof beams. A simpler method, the one which we used on the $500 house, was to simply run the girders directly from the high wall posts to the lower wall posts, then put on the roof beams.
You may either nail the posts to the girders, or, preferably, you may bolt them. Bolting has the advantage of allowing easier replacement of the posts in sixty or seventy years when they begin to rot out on the bottom.
To replace one you need merely roll back the carpet and polyethylene, jack up the beam slightly on either side, dig a hole in front and beneath the post and pull it down and out. With our system the retaining/ shoring is not nailed to the post so the wall doesn't come out with it. The wall should remain in place so long as you replace the posts singly. The new post must be notched the same dimensions as the old one and a new bolt hole drilled. Then it should be slipped into place and the earth tamped firmly beneath. Tamp more earth back around, smooth it to floor level, let down the jacks and replace the polyethylene and carpeting.
The process is slightly more difficult if the posts have been nailed. Ripping out the old nails and replacing them with new ones may gouge the girder some, but it is still feasible.
By this process all of the posts in the house may be replaced without disturbing the walls or roof, both of which should last nearly as long as the polyethylene which, as we have said, is expected to last indefinitely underground.
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