---
kind: "section"
citation: "24 C.F.R. § 3285.304"
title: "24"
number: "3285.304"
heading: "Pier configuration."
url: "https://uscodex.org/cfr/24/3285.304"
---

# §3285.304. Pier configuration.

- (a) **Concrete blocks.** Installation instructions for concrete block piers must be developed in accordance with the following provisions and must be consistent with Figures A and B to [§ 3285.306](/cfr/24/3285.306.md).
  - (1) Load-bearing (not decorative) concrete blocks must have nominal dimensions of at least 8 inches × 8 inches × 16 inches;
  - (2) The concrete blocks must be stacked with their hollow cells aligned vertically; and
  - (3) When piers are constructed of blocks stacked side-by-side, each layer must be at right angles to the preceding one, as shown in Figure B to [§ 3285.306](/cfr/24/3285.306.md).
- (b) **Caps.**
  - (1) Structural loads must be evenly distributed across capped-hollow block piers, as shown in Figures A and B to [§ 3285.306](/cfr/24/3285.306.md).
  - (2) Caps must be solid concrete or masonry at least 4 inches in nominal thickness, or hardboard lumber at least 2 inches nominal in thickness; or be corrosion-protected minimum one-half inch thick steel; or be of other listed materials.
  - (3) All caps must be of the same length and width as the piers on which they rest.
  - (4) When split caps are used on double-stacked blocks, the caps must be installed with the long dimension across the joint in the blocks below.
- (c) **Gaps.** Any gaps that occur during installation between the bottom of the main chassis beam and foundation support system must be filled by:
  - (1) Nominal 4 inch × 6 inch × 1 inch shims to level the home and fill any gaps between the base of the main chassis beam and the top of the pier cap;
  - (2) Shims must be used in pairs, as shown in Figures A and B to [§ 3285.306](/cfr/24/3285.306.md), and must be driven in tightly so that they do not occupy more than one inch of vertical height; and
  - (3) Hardwood plates no thicker than 2 inches nominal in thickness or 2 inch or 4 inch nominal concrete block must be used to fill in any remaining vertical gaps.
- (d) **Manufactured pier heights.** Manufactured pier heights must be selected so that the adjustable risers do not extend more than 2 inches when finally positioned.

## Notes

### Authority

Authority: 42 U.S.C. 3535(d), 5403, 5404, and 5424.

### Source

Source: 72 FR 59362, Oct. 19, 2007, unless otherwise noted.