Tree Roots, Root Barriers and Your Foundation

How roots draw moisture from clay

In a 2001 recommended practice, the Foundation Performance Association, a Houston-based nonprofit professional organization, wrote that trees "are now known or at least suspected to be the main contributor in the majority of foundation problems in the local market" (FPA-SC-04-0, Recommended Practice for Geotechnical Explorations and Reports, 2001, checked 2026-10-23). Its owner's guide adds that while roots can reach below a barrier, "most Roots will typically will stay closer to Grade to gather water and nutrients" (FPA-SC-20-0, Owner's Guide to a Better Foundation, 2016, checked 2026-10-17). The basics of tree-related warning signs live in the root barriers and drainage section of our signs page; this page goes deeper on barriers.

What a root barrier is

The FPA owner's guide sorts barriers into two kinds:

• Solid (physical): "usually made of 15 to 60 mil thick plastic, corrosion resistant metal, or reinforced concrete," with sealed joints. It notes that solid barriers "will also limit water movement across the barrier."
• Chemical: "normally a grid or net material with herbicide to limit root growth without otherwise harming the tree or limiting natural groundwater movement."

The same guide says barriers start "at or just below Grade and typically extend 24” to 36” into the ground," and can run right beside the house or in a half-moon or straight line near the tree itself (FPA-SC-20-0, Owner's Guide to a Better Foundation, 2016, checked 2026-10-17). The repair committee's older document makes the same split another way: mesh "will allow moisture to penetrate," while impervious barriers will not (FPA-RC-01-0, Post Foundation Repair Performance, 2004, checked 2026-10-19).

When engineers call for one

For new houses, the FPA's model drawing notes say trees "should not be planted closer than 20 feet to the foundation," and that if trees are within 20 feet, "a root barrier shall be installed" (FPA-SC-15-0, Foundation Construction Drawing Notes, 2008, checked 2026-10-15). Its owner's checklist asks whether large trees sit closer than 12 feet from foundations without root barriers (FPA-SC-20-0, Owner's Guide to a Better Foundation, 2016, checked 2026-10-17). For an existing house, a geotechnical report may recommend the "depth and extent of root barriers" (FPA-SC-02-0, Test Methods for Evaluating Existing Foundations, 2010, checked 2026-10-17), so ask a licensed professional engineer (TBPELS roster, checked 2026-10-19) whether one is worth ordering before a barrier goes in. We don't recommend a method.

Before cutting roots: ask an arborist

Trenching for a barrier cuts roots, so ask an arborist how close to the trunk a trench can go, and ask your city or HOA whether any tree rules apply before work starts. The root barriers and drainage section of our signs page lists what can go wrong after roots are cut.

Tree roots vs. other causes

A tree is only one possible cause. Plumbing leaks, poor drainage and seasonal drying can produce similar cracks, and our sinking foundation guide explains how a professional engineer sorts them out. A foundation inspection is the place to ask whether a tree is really involved. Steady watering in dry spells is covered on our foundation watering page.

Compare foundation repair options

Root barrier pricing isn't something we track. Pier and slab work after tree damage is a different job; the cost page credits each Houston range to its publisher. Quote requests are coming soon. For now, call (832) 646-1494 or email hello@steadyhomehouston.com.

When quote requests open, the contractor we refer you to will pay us for each referral; you pay us nothing. We're not a contractor.

Related: Signs of foundation problems · Sinking foundation · Foundation watering · Foundation inspection · Foundation repair guides · Home

Sources

• FPA-SC-20-0, Owner's Guide to a Better Foundation, 2016, checked 2026-10-17
• FPA-SC-04-0, Recommended Practice for Geotechnical Explorations and Reports, 2001, checked 2026-10-23
• FPA-RC-01-0, Post Foundation Repair Performance, 2004, checked 2026-10-19
• FPA-SC-15-0, Foundation Construction Drawing Notes, 2008, checked 2026-10-15
• FPA-SC-02-0, Test Methods for Evaluating Existing Foundations, 2010, checked 2026-10-17