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TroubleshootingPool Decking & Coping

Why is my pool coping loose?

Coping comes loose when its bond to the pool wall or deck fails: water gets in through open joints, freezing and thawing push on the masonry, or the deck moves under it. Coping is also the swimmers' handhold, so keep people off any stone that rocks. A sealed joint is a small repair; a stone that moves needs a masonry contractor.

Free to ask. Local shops send quotes, and you pay only when you book one.

By Kasra Taheri, Founder, LoclisPublished

Researched and drafted with AI, then checked claim by claim against the sources listed below before it was published. Prices and rules change; the dates beside each source say when it was last checked.

Step by step

Read when to stop and call a pro, further down this page, before you start.

  1. Step 1: Keep swimmers off it

    Tell everyone not to hang from or lean on the loose section, because coping functions as a handhold for bathers.[1] Mark it with a cone or tape until it is repaired.

  2. Step 2: Find every loose stone

    Press down on each stone by hand and tap it with a rubber mallet or the handle of a screwdriver. Mark any that rock, shift or sound hollow, and photograph them.

  3. Step 3: Look at the joint first

    Check the gap between the coping and the deck. If it is open, cracked or missing sealant but the stones do not move, the job is a joint reseal.

  4. Step 4: Check the width of the gap

    Measure the gap. The polymer sealant described below is made to fill cracks and joints up to 1 inch in width.[5] A wider gap needs a contractor.

  5. Step 5: Clean out the old sealant

    Cut out and scrape away failed sealant, then brush out dirt and debris so the joint is clean, frost free, sound and free of oils and greases.[5] The data sheet says not to apply over silicones or other existing sealants, so remove them completely.[5]

  6. Step 6: Pick a dry, mild day

    Avoid applying sealants below 40 degrees Fahrenheit, and avoid applying them when rain is imminent.[5] Wear nitrile gloves and eye protection.[5]

  7. Step 7: Seal the joint

    Run a thin bead of flexible joint sealant, with backer rod behind it if the gap is deep, because a thin bead accommodates more movement than a thick one.[5]

  8. Step 8: Let it cure

    Keep traffic off the joint for at least 3 days and keep the joint out of the water for 7 days, as the data sheet directs.[5]

  9. Step 9: Leave moving stones for a pro

    Do not re-bed a stone that rocks yourself. Note the locations from your photographs and ask a masonry or concrete contractor for a written quote.

Why coping comes loose

Coping is the cap along the pool edge, usually a series of bull-nosed stones that slope away from the pool.[1] It is held on by mortar or a bonding bed and by the joint where it meets the deck. When that bond or that joint fails, the stone starts to move.

The usual causes are water and movement. An open or cracked joint lets rain, splash water and pool water in under the stone. In Virginia winters that water freezes: as water within the concrete freezes, it expands and exerts forces on the adjacent concrete.[4] Repeated freezing and thawing can result in the concrete cracking and delaminating.[4] A deck slab that settles or heaves pulls on the coping, and a stone that was never well bedded can let go after a few seasons.

Why it should not wait

Coping also functions as a handhold for bathers,[1] so a loose stone is a safety problem and not only a cosmetic one. The same goes for chips and cracks. Public-pool inspectors apply a plain test: Los Angeles County's inspection guide says to mark IN if the coping is in good repair and free of cracks or uplifting, and to mark OUT if the coping is cracked, uplifted, or missing.[2] San Diego County's pool guide says that cracked or damaged decking, coping, gutters or steps must be repaired or replaced.[1] Those are public-pool rules, but the reasoning applies to a backyard pool.

An oval garden swimming pool seen from a tiled terrace with a white table
Photo: Unknown author, CC BY-SA 3.0, via Wikimedia Commons

Sort the problem by size

Start with the cheapest explanation. If the stones sit firm and only the joint where the coping meets the deck is open or cracked, you are looking at sealant that has aged out. Maintenance lists for Virginia pools include this job at opening time; the Virginia Department of Health's pool guide has the line "Deck is to be smooth/recaulk coping."[3]

For that joint, use a flexible sealant made for concrete joints, not a hard patch. Quikrete's Advanced Polymer Concrete Crack Sealant is formulated to fill cracks and joints in concrete, in interior or exterior areas up to 1 inch (25.4 mm) in width,[5] but read the label of whatever you buy for where it can be used and whether it suits a joint at the pool edge. Preparation is the part that decides how long it lasts: the substrate must be clean, frost free, sound and free of any oils, greases, or incompatible sealers, paints or coatings.[5] A thin bead of sealant will accommodate more movement than a thick bead,[5] so use backer rod in a deep gap instead of filling it with sealant. Avoid applying sealants below 40 °F (4 °C)[5] or when rain is close, which in Virginia usually means late spring or early fall.

What you should not try

A stone that rocks, lifts at one end or sounds hollow is a different job. It has lost its bond, and pressing it back with a dab of mortar rarely lasts. A mason will remove the stone, look at what is under it, clean the bed and set it again, and may find water damage that explains why it let go. If several stones are loose in a row, or the deck beside them has cracked or sunk, the cause is probably bigger than the coping. Read how to fix cracks in a concrete pool deck and whether to resurface or replace the deck before you decide how much to spend.

Stop and call a pro if

  • A stone rocks, shifts or lifts when you press it. Keep swimmers off it and have it re-set.
  • Several stones are loose, or the loose run is long. That suggests water or movement under the whole edge.
  • A stone is cracked, broken or missing. The LA County guide marks coping that is cracked, uplifted, or missing as out of compliance.[2]
  • The gap is wider than the sealant's 1 inch limit.[5]
  • The deck beside the coping is sinking, heaving or stepped. The deck is moving, and the coping will keep following it.
  • The pool is losing water. A leak behind a failed edge needs a pool leak specialist.

Hiring in Virginia

If the work you are considering is valued at $1,000 or more, a valid Virginia Contractor's License is required for the license category in which the contractor is to work.[6] Masonry contracting is a defined specialty: "Masonry contracting" means the service that includes the installation of brick, concrete block, stone, marble, slate, or other units and products common to the masonry industry.[7] Virginia law requires all licensed contractors to provide a written contract for residential work,[6] so ask for the scope, which stones will be re-set or replaced, and the price in writing. For budgeting, see what a pool deck redo costs in Virginia.

More guidance is in pool and spa answers and the pool and spa directory. When you are ready, describe the loose coping and licensed local contractors quote it.

Common questions

Is loose pool coping dangerous?
It can be. Coping is the stone edge swimmers grab, and a stone that shifts under a hand can cause a fall or a pinched finger. San Diego County's pool operator guide says that cracked or damaged decking, coping, gutters or steps must be repaired or replaced. Treat a rocking stone as something to fix soon, and keep people off it until then.
Can I re-set one loose coping stone myself?
It is better left to a mason or concrete contractor. A stone that moves has usually lost its bond for a reason, such as water getting under it or the wall or deck moving, and bedding it again in mortar without finding the reason tends to fail again. Resealing an open joint is the repair most homeowners can do.
Can freezing weather loosen coping?
Yes. The National Park Service notes that as water within concrete freezes, it expands and exerts forces on the adjacent concrete, and that repeated freezing and thawing can result in cracking and delaminating. Water that gets into an open joint or a cracked stone in a Virginia winter is the usual route.
Do I need a licensed contractor to repair coping?
If you hire someone and the work is valued at $1,000 or more, DPOR says a valid Virginia contractor's license is required for the license category in which the contractor works. Masonry contracting and concrete contracting are both listed specialties. Smaller jobs you do yourself need none.

Sources

  1. [1] Swimming Pool Operator's Guide, 1st Edition, County of San Diego Department of Environmental Health, Food and Housing Division. Checked October 28, 2026.
  2. [2] Public Pool Inspection Guide, Los Angeles County Department of Public Health, Environmental Health. Checked October 28, 2026.
  3. [3] Pool Operation and Maintenance Guide (compiled 2018), Portsmouth Health Department, Virginia Department of Health. Checked October 28, 2026.
  4. [4] Preservation Brief 15: Preservation of Historic Concrete, National Park Service, U.S. Department of the Interior. Checked October 28, 2026.
  5. [5] Advanced Polymer Concrete Crack Sealant, product data sheet, The QUIKRETE Companies. Checked October 28, 2026.
  6. [6] What You Should Know Before You Hire a Contractor, Virginia Board for Contractors, Department of Professional and Occupational Regulation. Checked October 28, 2026.
  7. [7] 18VAC50-22-30. Definitions of specialty services (Board for Contractors Regulations), Virginia Administrative Code, Virginia General Assembly. Checked October 28, 2026.

Want a pro to handle it?

Describe the job once. Licensed local businesses send quotes, and you pay only when you book one.