Shimming adjusts a bearing interface in a pier-and-beam system. It should be specified only after the provider determines why a gap or alignment problem exists and whether the surrounding members are suitable.
The presence of shims is not automatically a defect, and a proposal to add shims is not automatically a complete repair. The location, material, bearing and underlying condition need explanation.
Identify the actual gap
Ask the inspector to show where the gap is and which members meet there. Is it above a pier cap, beneath a beam or somewhere else? Request a photograph and a location on the room plan.
ASCE’s regional guidance discusses hardwood or steel shims at pier caps as one repair measure. It is not a universal detail for every foundation or permission to stack improvised materials. ASCE Texas Section: Residential Foundation Guidelines (2022; regional technical guidance)
| Question | Evidence to request | Why it matters |
|---|---|---|
| Where is adjustment needed? | Marked support location | Connects work to the symptom |
| Why is the gap present? | Inspection explanation | Tests whether adjustment is enough |
| Are bearing members sound? | Condition assessment | Avoids covering unresolved damage |
| What material is specified? | Written detail | Defines the actual repair |
| Is lifting included? | Objective and monitoring plan | Sets expectations |
| What supports the pier? | Bearing assessment | Addresses the whole load path |
Separate shimming from deterioration repair
If a beam is damaged or a support has moved, ask what work addresses that condition. A gap adjustment should not conceal an unresolved problem in the member or bearing below it.
USDA’s wood guidance explains that decay affects more than surface appearance. Ask for structural condition to be assessed separately from a decision about cleaning or drying. USDA Forest Products Laboratory: Wood Handbook, Biodeterioration of Wood (2021)
Have the quote identify any wood replacement, reinforcement, moisture correction or support work that accompanies the adjustment. Different tasks should have identifiable locations and responsibilities.
Ask about the intended floor change
Does the proposal aim to restore contact, stabilize a specific area or change floor elevation? Ask how the contractor will determine whether the objective is met.
If lifting is involved, discuss potential effects on connected finishes and services. Request the procedure for monitoring and stopping decisions from the qualified provider; do not attempt to copy the operation from an online diagram.
Review materials and installation details
The scope should specify the relevant materials and bearing arrangement. Ask which design or professional guidance applies to the property. Avoid accepting a description such as add whatever fits.
Request photographs before and after the work and any required inspection documentation. Ask what will remain accessible for future inspection. If the crawl space is being enclosed, coordinate the sequence so bearing details can be recorded first.
Compare the full project
A small adjustment quote may exclude investigation, access, wood repair, moisture work or restoration. Compare bids against the same scope rather than the word shimming alone.
Ask how additional findings will be handled. A clear change process is particularly useful where inspection access is limited. Require an explanation before expanding a localized adjustment into a much larger project.
Preserve the maintenance record
Keep the locations, date, materials and purpose of the adjustment. Note what changed upstairs afterward and what remained. If the original symptom returns, provide this record for reassessment.
Do not assume a repeat symptom means the same adjustment should simply be repeated. Ask whether the support, framing or moisture conditions have changed and whether the original diagnosis remains appropriate.
Frequently Asked Questions
Are shims always a temporary fix?
The answer depends on the designed detail and the condition being addressed. Ask what makes the proposed installation appropriate for its intended use.
Can shimming repair rotten wood?
Do not treat an adjustment as restoration of a damaged member. Ask for the wood condition and any required repair to be evaluated.
Should every support have the same shim arrangement?
The actual support conditions govern. Request a location-specific explanation rather than a uniform visual appearance.
Related Services
See pier and beam repair or request an assessment.
Research Sources
Sources reviewed September 6, 2026. Inspection and quote questions are an editorial checklist; actual repair requirements depend on the property.