Support Pier Types

Gregg Henderson, Dunaway, Christopher R.  |  4/18/2005 8:27:15 PM

Figure 1: Brick pier

Figure 2: Termites tunneling over cinderblock pier.

Figure 3: Concrete cap can expose termites

Figure 4: In this case the concrete pad is at the bottom and termites must expose themselves to get to the cinderblock.

Figure 5: The concrete slab above the brick will expose any termites getting through the mortar on their way into the house.

Figure 6: The solid concrete slab with a termite shield ensures that termites will have to expose themselves.

Brick and Mortar Piers


Brick and mortar piers, common in most of the old homes in New Orleans, are some of the most difficult to inspect and treat. The problem is that Formosan subterranean termites can travel through the center of the pier as easily as they can travel up the exterior. Furthermore, it is difficult to apply a continuous chemical barrier that the termites cannot bypass. (See figure 1.)

Proper treatment requires that the soil around each pier be treated by trenching or drilling. Each pier must then be drilled between every other brick to reach the center and chemical applied to the holes.

Inspection:

Look at all four sides. Carefully examine the sills, floor joists and sub-floor in the area around each pier for signs of infestation like shelter tubes or damaged wood. A screwdriver or similar tool us useful for probing the wood.


Hollow Block Piers

With this type of pier, subterranean termites can enter the structure by tunneling up the outside of the pier (as seen in figure 2) or they can travel through the center. Proper inspection requires that each pier be examined on all four sides and that the wood above each pier be examined for signs of damage and infestation.

Treatment requires adding a chemical barrier around all four sides of each pier by trenching or drilling. The interior of the blocks should also be treated by drilling each void or pouring the product in from the top when possible.

Inspection: Similar to that of brick and mortar.

Both brick and hollow block piers can be greatly improved with the addition of solid concrete bases or caps.

  • Concrete caps prevent termites from tunneling straight through the piers and into the wood. Therefore if the termites are able to penetrate the treatment barrier, they can easily be spotted when forced to tunnel around the cap.
  • For proper treatment, the pier should still be drilled and treated.
Figure 4 shows that concrete pads are similar in that the termites need to tunnel around the concrete to get into a structure, thus giving you the opportunity to detect the infestation easily.

Solid concrete pads also easier to treat since only the soil around the perimeter of the pad needs to be treated and not the interior of the pier.


The concrete pad must be solid with no cracks or holes and extend above the level of the soil.


In figure 5, this brick pier sits on a solid concrete chain wall and has a solid concrete cap. Two thumbs way up!


Figure 6 represents the winner for best pier goes to solid concrete. For ease of inspection, treatment, and durability there is no better selection.



Treatment:

Trench and treat the soil around all four sides of each pier.


Inspection:

Examine all four sides of each pier for shelter tubes.


Given a choice I would build a pier and beam house with solid concrete piers with at least 2 feet of clearance underneath.
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