Teleposts require small, slow adjustments

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This article was published 10/03/2002 (8826 days ago), so information in it may no longer be current.

QUESTION — We recently moved into a bungalow built in 1965. The floor plan is an L-shape. Steel beams and teleposts were used to support the structure. The main run has four teleposts equally spaced along the length, and a single post supports the secondary steel beam under the rear wall of the master bedroom. The floor joists along the main beam run from the foundation walls to the steel beam, where they overlap from either side.

The basement was fully finished and the four teleposts along the main beam were enclosed within a wall. The ceilings in the basement are acoustic tiles, nailed to strapping set perpendicular to the floor joists. Access to the posts is not an issue, as we intend to rework the basement.

Our challenge is that the teleposts have never been maintained. With settling over the years, a hump in the floor has developed along the run of the steel beam. The hump covers about two feet either side of the beam, with the floor at the centre of the beam being 1/2-inch to 5/8-inch higher than the rest of the floor.

We seem to have two options to get the floor back to level. We can lower the teleposts quickly, or over an extended period.

From what I can see of the teleposts, there is about 1.5 to 2.0 inches of thread showing at the upper ends. I would like to lower them slowly over the next few months or a year, but I cannot figure out how much drop I can expect from one rotation of the telepost screw. No manufacturer’s name is visible on the posts. What can I expect with this type of adjustment, or do you know of a formula for determining telepost adjustments?

–David Dunlop, e-mail

Answer — Steel teleposts are installed with adjustable heads to compensate for movement in concrete basement floor slabs and the footings beneath.

The teleposts should sit directly on the footing or on a raised concrete pad above the footing, in older homes. These footings may move due to expansion and contraction of the soil underneath. The teleposts also will allow for adjustment due to settlement of the perimeter foundation in relation to the inner footings.

In most cases, the teleposts will have to be adjusted downward as the footings or floor slabs heave as the foundation settles. This appears to be the case in Dunlop’s home, causing bowing of the main beam above the posts and humps in the main floor. This can be minimized with slow, careful adjustment of the screw heads at the top of the teleposts.

There is no formula, that I know of, to lower teleposts, as it depends on the amount of adjustment required and the movement of each post relative to the perimeter foundation walls.

Dunlop appears to be well informed about the need to adjust the teleposts, but should be cautioned that he may never be able to level the floor but should strive to straighten the main beam. The beam may be substantially lower at one end than the other, due to uneven settlement of the foundation walls.

This is often done by running a tight string line from one end of the beam to the other, dropped slightly by equally sized spacers at both ends. Partial removal of basement walls or ceilings may be necessary to accommodate the line. If this is not possible, a transit level or laser may be used to pinpoint existing beam heights. Once this is done, measurements can determine the amount of lowering required at each telepost to straightened the beam.

My own advise to homeowners is to lower the posts as slowly as possible, allowing maximum time for the house to adapt after each adjustment. This will minimize the cracking in the walls above the beam and prevent loosening of floor sheathing and other structural components.

A quarter turn of the screw every two to three weeks is the rate I often recommend. The individual teleposts likely will require different amounts of adjustment, and I suggest Dunlop write down a schedule for adjustment of each post. Perfect straightening of the beam is unlikely and a timeframe of several months should be allowed to get the beam to a reasonably straight position.

Ari Marantz is owner/inspector of Trained Eye Home Inspection Ltd. and is the PR Rep. for the Canadian Association of Home Inspectors, Manitoba (www.cahi.mb.ca). Questions can be e-mailed or sent to: Ask The Inspector, PO Box 69021, #110-2025 Corydon Ave., Winnipeg, MB. R3P 2G9. Ari can be reached at 291-5358.

trainedeye@iname.com