Posted by: sanderling | 2015 July 25

Beginning to rise: rim joists

With the sill plates finished, I faced the same problem: where to get decent pressure treated wood? Back to an online search; still no 0.40 pcf wood to be found anywhere near Flagstaff. The best I could find was some 0.20 pcf hem-fir was at the Lowes in Prescott, some two hours to southwest.

Rationalization: The joists will sis atop the 0.40 pcf sill plates, separated from the ground and any termites by the piers, copper shields and the sill plates. So it ought to be okay, right?

Besides, if one goes by way of Williams and Ash Fork, it’s a pretty drive, mostly.

Right. So on to Prescott, where it’s in the mid-90s rather than the low 80s. (I do like Flagstaff!) I loaded up with 21 10 foot long pieces of 2×6, and two 8 footers – enough for the rim joists plus 19 joists. Unfortunately, I forgot about the blocks (or as they’re often called, bridgers) which should have been of the same stock.

Fortunately, the wood looked good. P-T wood is “wet” so you don’t know how much it will warp or twist or bow as it dries, so you look it over as carefully as you can … and hope for the best. Plus, like all the lumber sold around here, the vast majority is plain sawn, which means it is composed of inferior cuts which are naturally prone to warping, cupping, twisting or bowing as they season. The quicker you can get it installed with solid fasteners to hold it in place, the better … but even in Flagstaff, the sun is hot and the air is dry so you know you’ll have problems. (What I didn’t notice is the the stock varied a bit in width, which was to complicate matters when it came to fitting joists.)

Sill plates with rim joists in place

Sill plates with rim joists in place

First up was installing the rim joists. They’re planks that sit on edge parallel to and on the outside edge of the outside sill plates. It’s important that their faces be vertical, as the joists will butt up against them. One ten foot and one eight foot plank was used on each side of the frame. I waited until they were installed to cut them to length.

I used squares and clamps to hold them in place while I drilled pilots holes for 5 inch ledger screws (I used FastenMaster LedgerLock ledger board fasteners which are coated for resistance to wood preservative) and then drove the screws up from the bottom of the sills. The ledger screws had hex heads so I drove them with a socket wrench, which was a lot easier than driving a screw up from below with a screwdriver would have been, as well as a lot more secure that toe-nailing.

It was a pretty straight-forward, quick and easy job. The rim joists will need scabs (short pieces of wood used to link butt-ended components, rather similar to sister-planks or -boards used by boatwrights) but I’ll install them a bit later.

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Posted by: sanderling | 2015 July 22

A perplexing scarcity

With the foundation piers finished, it became time to move on the the sill plates, or mudsills. But first, a thought for some dreaded insects: termites.

Yes, termites. They’re a problem in northern Arizona, much as they are elsewhere in the country. Worse, the county’s building department warned me that they’re a particular concern in the area where I’m building. Their warning, coupled with just plain common sense, caused me to look into local practice, and locally available supplies. I didn’t find any generally observed practice among the builders I consulted, although further consultation with the building department, various books and good ‘ol Mr. Google suggested a course of action: sand barriers, termite shields, and the use of 0.40 pcf (pounds of preservative per cubic foot of wood) pressure treated lumber for sill plates, plus continued vigilance. Which sounds pretty logical to me … and even if it’s a bit of overkill (no pun intended!) it seems to me that using all four approaches is cheap insurance.

So I started looking for termite shields and 0.40 pcf lumber. None to be had in Flagstaff! Not even close – no termite shields at all, and the best offerings in PT lumber were in the 0.10 pcf range, and frankly, the wood didn’t look too good in any case. In fact, Mr. Google and I couldn’t find a source for either anywhere in Arizona.

Ultimately, I bought some termite shield, but I had to do it online. The product I got was a 60′ roll of 12″ wide YorkShield 106TS laminated copper termite barrier. I only need about 20’ of it for this project, but I figured that if I liked the product I could use the remainder on buildings to come.

Searching online, I also found a Lowes in southern California which carried the 0.40 pcf lumber I wanted; fortunately, I was already planning to visit my father there, and it happened that the Lowes in his town had a good supply of the wood … so I returned home from the visit with my sill plate wannabes loaded aboard my pick-up.

The literature I’ve found on sand barriers specifies that the sand (cinders will also do) should be 16 grit – not bigger, and not smaller. Unfortunately, I have yet to find a source for 16 grit sand or cinders, or to locate appropriately sized mesh for me to develop my own source. I think I’ll pass on the sand barriers for the shed, but revisit the issue when it comes to the other, more substantial buildings. After all, I have cleared the soil underneath the shed of all plants and wood-related debris, and the minimum height of the piers is over the seven inches minimum recommended by the county, and I’ll have the copper termite shields and the 0.40 pcf pressure treated sill plates. As time goes by, it should be easy to check the piers for any sign of termite tunnels, too. I think it will be okay.

At least with the wood and termite shield material in hand, I could get to work.

The termite shield is ridiculously easy to work. It cuts easily with shears, it’s easily drilled, and very easily formed. The copper sheet seems awfully thin, but all it has to do is stop a termite. It’s tougher than it looks although I suspect it would still be easy to rip, but if that happens, it should be easy to seal the rip with a construction-grade sealant. That has to be done around the anchor bolt holes in any case.

Every project seems to take longer than anticipated. The termite shield was a welcome exception. The only tricky part was drilling the hole for the anchor bolt. The drill must be run at a very low speed, or the bit will rip the copper. However, this was an easy adjustment to make. Each pier was unique (especially in the placement of the anchor bolt) so there was no mass production. But the work went quickly, even the folding down of the edges at the recommended angle of 45 degrees, and folding them together to form the downward-sloping corners.

Once they were in place, but before I used the sealant around the anchor bolt holes, I started fitting the sill plates. Each plank is a 2×8, but I was a little worried about the six foot spans between piers and with the inevitable warping and twisting of the planks, so I decided to double them, screwing the upper and lower planks together to so they would reinforce each other and tend to counter any warping or twisting in the mated plank. The result is a more stable, more level and stronger base for all further building.

Termite shields and mudills in place, under the watchful gaze of the project manager

Termite shields and sill plates in place, under the watchful gaze of the project manager

By the way, fasteners need to be resistant to the corrosive effects of the wood preservative steel fasteners are not sufficient. I used 2 1/2′ stainless steel screws to fasten the upper and lower sill plates together.

To further strengthen the, I overlapped the joints. The building – and thus, each sill plate – is 18 feet long, so I used staggered 12 and 8 foot lengths, trimmed so that each plank would be anchored by two bolts. All this complicated the assembly somewhat, but not excessively so.

I test fit each piece, carefully measuring the location of each anchor bolt (or so I thought; it turned out that I needed to enlarge a few of the holes as I didn’t get my measurements quite right). As I test fitted the pieces, I also checked for squareness, measuring and comparing the diagonals … and found to my relief that they differed by less than a 16th of an inch. With all the pieces cut and bored to fit, I sealed the anchor bolt holes in the termite shields, assembled the lower layer of sill plate planks, fit the upper layer on top of them, and screwed them together with 2 1/2″ stainless steel screws.

Posted by: sanderling | 2015 June 27

Return to work

March ended, April came and went; still freezing at night. But on May 2, work began afresh.

Over the winter and had refurbished the per form. It was my own design, and it could have been better designed! For one thing, the plywood sides were too thin: 1/2 inch plywood would have worked better than 3/8. For another, the 1×2 reinforcements were too short, whit the result that the pressure of the concrete pours had cracked some of their ends, preventing a tight fit along the corners … which, in turn, permitted fresh concrete to leak out.

But by the 2nd, these faults had been addressed, if not remedied, mostly by new and stronger reinforcements, and also by using light line, tightened with a small Spanish windlass, to hold the sides tightly together.

So the seventh pier was poured on May 3. Removing the form had to wait at least a day for the concrete to cure enough to be solid, and then the form had to be cleaned, fitted with different “skirts” to adjust its height, and carefully position for the next pour. But the next pier was poured on the 7th, the ninth followed on the 13th, the tenth a week later, the eleventh four days after that. And the final one was poured on June 1.

Final pier, freshly poured

Final pier, freshly poured

Two days later I removed the form, and carefully checked the twelve piers for level. Eureka! The extremes were plus or minus about a 16th of an inch (1.6 mm), most were closer to level than that, and none was more than 1/16 of an inch above or below the level of its neighbor. I had assumed I would need to shim the sill plates, but those results were far better than I had hoped!

Twelve piers, completed

Twelve piers, completed

And I was done with digging holes, schlepping aggregate and cement, and hand mixing concrete in a wheelbarrow. Now the fun part – working with wood – could begin!

Posted by: sanderling | 2015 June 24

Winter hiatus

Flagstaff sits at an altitude of 7,000 feet (2,130 m.). The air up here is thin and cool … and downright chilly come winter. The area’s nightly low temperatures average below freezing from late October well into May, which means that do-it-yourself concrete work pretty much comes to a halt once winter starts dragging its cloak across the land.

IMG_1723 Exploring the work site, winter

Exploring the work site

I was hoping to get the piers finished before the nights got too cold, but by the time winter set in I had just 6 of the planned 12 piers finished, and only seven footers poured. We had a brief warming spell in March, and I was able to dig the remaining holes and pour the final footers, as the freshly dug holes reached earth that was comparatively warm and the days warmed up to the high forties and low fifties, so the fresh concrete stayed warm enough long enough to set up adequately.

But that was it, until the weather warmed up some. Which it didn’t do until early May. Oh well – I love Flagstaff’s weather just the same!

Posted by: sanderling | 2014 September 29

Third cast

The third pier went smoothly.

No problems with the digging or the footer.

Because of the site’s slope, the pier needed to stand further above grade, so I replaced the short “skirts” used to elongate the form with longer ones. The additional height above the ground also necessitated using concrete blocks to provide a (relatively) higher platform for the adjusting bolts … and it meant more cement – whereas the first pier needed about four cubic feet of the stuff, this one needed about five and a quarter.

Newly poured third pier

Newly poured third pier

The pour went smoothly, as did the release of the form the next day. The only problem was that I didn’t do an adequate problem of tamping down the fresh concrete as I poured, so there were a couple of small voids at the corners, but there’s surely a lot more concrete in the pier than absolutely needed to support the structure and these central piers will be quite protected from the weather, so I doubt that it’s a concern.

Starting with this pier, I’m also using longer anchor bolts. Winter’s winds can be quite strong in this area, and temblors are a possibility, so I want to make sure the structure is well anchored.

Onward!

P.S. You’ll note in the photo that by this time, the hole for the fourth pier had already been dug. In addition, the footer was poured too – that was all done on the 16th.

You’ll also note the six foot level, which I’m using to ensure that the piers are, indeed, at the same level. Through these first three, the variance between piers is less than an eighth of an inch.

Posted by: sanderling | 2014 September 26

Second pier

Buoyed by the success of the first pier, I was eager to pour the second. Because of the slope in the site and a slightly deeper hole and footer, I added one inch “skirts” to the bottom of the form. Then I oiled and leveled the form as before, and mixed & poured the cement. This time, no pigment, as the pier would be under the middle of the building, and nigh on invisible.

But I made an error in judgement about the skirts. Even with the extra inch, there would still be about another inch between the bottom of the form and the footer, i.e., there would be a one inch gap between the bottom of the form and the footer. I figured it wouldn’t be a problem – concrete is thick and as all the gravel in it, right?

Wrong.

When I went to remove the skirt the next day, I discovered that some of the cement had oozed through the gap and risen far enough to establish a firm grip on the skirts. So I had to dig down along side of the new pier to get enough room to break away some of the errant cement and remove the form.

No real damage, except to one of the skirts.

Another lesson learned.

Posted by: sanderling | 2014 September 21

Cast in concrete

Of course, the proof of the form was to use it. So I did.

The first step was painting the insides of the form with motor oil. Cheap motor oil. Using a cheap brush. Nice and messy – use old pants!

Then, after cleaning off the footer (bits of dirt had fallen into the hole), I positioned the form inside the hole, atop the footer. Then I laid boards down alongside of the hole and put a 2′ level on top of the form. After positioning the form north-and-south, and east-and-west, I used the “adjustment bolts” bolts to level it, alternately tightening or loosening the adjustment nuts as necessary to bring the form to the correct height and to make it level. It’s an easy process, but a little tedious.

Pier form in place

Pier form in place

Then mix cement. It’s a tiresome process, and definitely tedious. Especially tiresome since all the materials – cement, aggregate and water – have to be carried to the site, and since I don’t yet have power to the site, all the mixing is done in a wheelbarrow. What fun.

Then to (carefully) shovel the fresh concrete into the form. And shovel, and shovel, and mix some more, and shovel it, and then mix some more. Along the way, I inserted some 3/8″ rebar and an anchor bolt (to secure the mudsills and ultimately the entire structure; this area isn’t prone to major earthquakes, fortunately, but minor temblors aren’t uncommon.)

First pier in form

First pier in form

When sufficient concrete was in the form to almost reach grade level, I added red and brown pigment to the mix, aiming to come up with a color approximating the surrounding soil (I don’t like the grayish-white of native concrete). And then I shoveled some more. Until the concrete was flush with the top of the form, at which point I troweled it.

And stood back and admired my work.

Then the really fun part: cleaning up. Ugh.

I figure I’ll let the concrete set up for about a day, and then pull the form off. Or attempt to. We’ll see.

Posted by: sanderling | 2014 September 20

Form: functional?

The whole point of digging holes and casting footers for piers is to cast the actual pier. But the question is, how should I go about it?

One option that I liked was to use Sonotubes or an equivalent competitor’s product. A Sonotube looks like the cardboard core to a gigantic paper towel roll. That’s because that’s essentially what it is: a cardboard sheet spiraling together to form a cylinder. The big difference between a Sonotube and a paper towel core (besides size) is that the Sonotube is waxed so that concrete won’t adhere to it. The idea, then, is to cut a Sonotube to the proper length, place it on top of the footer, and pour concrete into it. Viola! A nice, cylindrical pier (with a characteristic spiraling line running up it). I’ve used Sonotubes before, and liked them.

But the problem with a Sonotube is that it creates a cylindrical pier. I wanted rectangular piers, so they could be close to the edges of the shed without having part of the cylinder protrude beyond.

So I decided to build my own form. Moreover, I wanted it to be reusable (which a Sonotube isn’t). I decided to make it out of cheap (i.e., thin) 3/8″ CDX plywood reinforced by cheap 1×2 stringers. The top, i.e., the bearing surface, would be slightly smaller than the top of a concrete block, i.e., 7 1/2″ x 15 1/2″ – nothing magical about that size, but the plans I’m working from call for concrete block piers, and I decided to follow suit, narrowing it a bit to match the 2×8″ mudsills that would be bolted to them.

Reusable form for casting concrete piers

Reusable form for casting concrete piers

To make the form reusable, it had to be removable. I decided to combine three separate features to achieve that. First of all, the form would taper. Each side is a tall trapezoid, four inches wider at the base than at the top. This, I hoped, would enable it to be lifted straight up. Second, each side was designed to be readily (and non-destructively) removable in place. To do this, I used three sets of 1×2 horizontal stringers to reinforce the plywood … and to overlap at the corners, with 3/16″ lag screw eyebolts with connecting those stringers. I figured that after the pier was cast and had a chance to cure, I could disassemble the form in place if necessary. And the third feature was an old standby: a liberal coating of the form’s inside surfaces with cheap motor oil, to serve as a release agent.

Vertical stringers reinforce the plywood at the corners. The result looks more complicated than a simple form made of thick plywood, but it’s lighter and cost less to build.

Because the land slopes a little, and the footer depth would be uneven in any case, I knew that form had to be adjustable for height. It also needed to be adjustable for level, in case the footer wasn’t. To solve the first problem, I made room for the addition of “skirts” at the bottom, to be added, adjusted or removed as necessary to ensure the correct height. To accomplish the second goal, I extended the horizontal stringers attached to the narrow sides, and mounted adjustable bolts through them, to be used to ensure that the form’s top is level.

It’s a funny looking thing, but I think (and hope) it will work.

Posted by: sanderling | 2014 September 16

This is getting repetitive

Dug the fourth hole. Made it a little wider and longer. Like the others, it’s about 38″ deep to get well below the frost line. And since the site slopes about 6″ inches, its pier will be the tallest in the row.

Posted by: sanderling | 2014 September 14

Third hole, just like the second

Another dry day. Pretty, with lots of clouds and sunshine, but no rain. Dug a hole for the third pier, and poured the footer.

This is becoming rather routine already … and tedious. Digging holes and mixing & pouring concrete are necessary tasks, but not nearly as fun as framing. Oh well. I hope to keep plugging away so I can finish the concrete work before winter sets in.

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