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Many of the old wood-frame buildings in my region were originally built on full-basement masonry foundations with masonry piers supporting the first-floor carriage beam at midspan.

It may seem that a brick pier makes an ideal choice for this task, especially when compared with a decay-prone wood post. But over time, many of these piers have deteriorated in response to the effects of rising damp, which is the movement of ground moisture up through the concrete footing into the brick. Once that happens, salts in the mortar — typically calcium sulphate — can dissolve, leaving a crystal deposit in the pores of the brick. Gradually, the crystals accumulate enough that the pressure inside the pores shatters the brick. Efflorescence — that white powdery calcium dust that appears on the surface of masonry exposed to moisture — is a clear indication of rising damp.

I'm occasionally called on to replace these piers. We often find light-duty adjustable steel columns installed under the beam as a stopgap measure against settling. These columns are not meant for permanent application, and they're not usually placed on a structural footing. So we install concrete-filled Lally columns on top of new poured footings.

I don't like to jack up old wooden beams that have sagged over time. The wood fibers have usually taken a set, making the beam impossible to straighten, if it was ever straight to begin with. Jacking would just crack the beam and the plaster in the rooms above. Instead, we install our steel replacement posts so as to transfer the load without any need to lift the floor system in the process. But simply wedging the plate and post up on a new footing and grouting under the plate won't preload the column, which is critical in avoiding any further settling of the structure.

On the job shown here, we replaced the masonry piers with 3 1/2-inch-diameter Lally columns, as specified by the engineer. Lally columns are typically sold with 4-inch-square stamped-steel base and top plates. Raised lugs help center the plates on the column, but they are only about 1/8 inch high and don't do much to restrain the column against incidental vibration and movement. So we used "Springfield plates," which are 6-inch-by-8-inch-by-5/16-inch-thick steel plates with a 1-inch-high welded collar to accommodate 3 1/2- and 4-inch-diameter columns. We had these welded to 9-inch-by-9-inch-by-1/2-inch-thick steel plates, with precise 1/2-inch holes drilled at the four corners for anchoring to the footings.

We broke through the old concrete slab and dug holes for 24-inch-by-24-inch-by-12-inch-deep footings. When we poured the footings, we added crossing layers of three #5 rebar for reinforcement, but poured only 7 inches of concrete to begin with.

After the concrete set up (about 48 hours), we temporarily shimmed the base plates level on top of the footings so they would lie flush with the floor slab [1]. Next, we lag-bolted the top plates to the underside of the carriage beam, centered plumb above each footing [2]. We used steel washers to shim the plate level on the rough beam surface. Because of the dips in the beam and the general irregularity of the basement slab, each column had to be cut to a different height. To measure, we used two pieces of strapping held together with a couple of C-clamps and slid apart lengthwise to gauge the distance between each top and bottom plate. This method is easy and more accurate than a tape measure, and can be transferred directly to the column to mark the cut.

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Lally columns are easy to cut in the field with a large-diameter cutter and a pipe vise [3]. The concrete column core breaks off rough, so we use a 41/2-inch grinder with a diamond blade to smooth the ends.

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While each column was still held in the vise, we clamped a pair of 36-inch-long 2x4 crossties to it, about 12 inches up from the bottom. I like to make the clamps with Dayton threaded rod, which is used to connect concrete forms. It has a coarse thread that allows the nuts to spin with ease and without cross-threading. To either side of each footing, we stacked 6x6 cribbing to support the crossties and hold the column upright in place, with the top captured in the Springfield plate [4].

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For both anchoring and adjusting the base plate, we ran 7-inch-long 1/2-inch-diameter carriage bolts through each hole, with the heads facing down, like legs, resting on 3/4-inch washers to help spread the temporary load. With each head centered on the washer, like a pivot bearing, we could precisely position the plate above the slab without deflection from irregularities in the concrete [5].

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We fit the base plate under the column and snugged it up hand-tight. (I mentioned earlier that I'd had precise, 1/2-inch holes drilled through the plates. If the holes had been made larger, the legs would tend to heel over and cause problems with adjustment.)

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At this point, we could have used the bolts to load the columns, but that's a slow process. Instead, we used a 10-ton hydraulic pancake jack under the base plate [6]. The ram part of the jack is only a couple of inches high and has a 15/8-inch throw. We checked the column for plumb and slowly applied jacking force. A temporary adjustable post shore placed immediately next to the footing under the beam (and nailed at the top to prevent accidental spills) provided a simple means of monitoring the load transfer. As soon as I felt some slack in the shoring post, I knew the permanent column was preloaded. At that point, all we had left to do was tighten up the bottom nuts under the base plate, place top nuts on the bolts, and release and remove the jack.

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To finish off the footings, we poured the balance of the concrete within 3/4 inch of the base plate [7]. Once the concrete set, we dry-packed mortar under the plate. In all, we installed 12 posts on this job without cracking any plaster.

Mike DeBlasiois a masonry contractor in Littleton, Mass.


Roof Demo by Crane

by Mark Parlee Last year, my company was hired to frame a large addition on a ranch. Most of the building was to remain, but at one end we had to demolish the roof and walls without damaging the floor system below. Tearing down the roof in place would have been slow and dangerous, so instead we brought in a crane to lift it off in sections.

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In preparation, we gutted the interior, cut the trusses free from the walls, and broke the gable roof into three sections by slicing through the sheathing and truss braces. Next, we cut four holes through each section of roof and tacked LVLs to the bottom of the trusses. When the crane arrived, we dropped cable through the holes in the first section of roof, wrapped them around the LVLs, and used shackles to connect them to the lifting straps. After the crane operator lifted that section and placed it on the ground about 50 feet away, we repeated the same steps with the other two sections. Since the crane was there anyway, we also used it to lift some of the exterior walls. The $900 it cost to bring in the big machine was well worth it: Dismantling the roof on the ground turned out to be safe and quick.

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Mark Parleeis a general contractor in Des Moines, Iowa.


Working Wireless

by David Grubb There are two routers on my current remodeling job: One spins carbide bits and the other pro-vides a WiFi network so I can connect wirelessly to the Internet. The latter came about because the clients used a wireless router to access their broadband connection, and when they moved out they said we could use it.

Wireless is great on a remodeling job, because setting up a permanent site office is rarely practical. As soon as you set up in one room, you get chased out when the crew and subs need to work there.

With the wireless network, I can take my laptop anywhere in the building to do e-mail or access the Internet. In the past, this stuff had to wait until I could get back to my office — usually at the end of the day. Now, when I have questions for the owner, architect, or engineer, I can send e-mail messages straight from the job. I still use my cellphone, of course, but I actually prefer e-mail because it leaves a paper trail for documenting decisions.

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The architect on this particular job has been e-mailing drawings as PDF files, a format that just about any computer can read. He'll send a section drawing for a television cabinet, for instance, and I'll forward it to the cabinetmaker and the audio installer at the same time. It's easier and more reliable than sending a fax.

I use a digital camera to document the job, and there are times I want to access those photos on site. In the past, they'd sit on my office computer because there was no point bringing a laptop to the job when I couldn't connect to anything. These days, if we run into an unexpected condition, I can immediately e-mail a photo to the architect or engineer, and there's a good chance I'll get an answer the same day.

Most of my clients have broadband access, but if the next one doesn't have a wireless router, I'll bring my own. The routers cost less than $100, and unless your computer is really old, the connection is easy to set up.

David Grubbis a remodeler in Berkeley, Calif.