How do we replace failed sealant and caulking on our HOA buildings?

By OurHOA · General information · Revised September 27, 2026

How an HOA board replaces failed exterior sealant and caulk: water testing to find the leak, the right sealant for each joint, PCB checks, adhesion tests and bids.

Part of the HOA board handbook: vendors, projects and upkeep.

The short answer

Find where the water gets in before you pay anyone to recaulk. Hire a building envelope consultant or engineer to water test the leaking spots, then write a spec that says which joints get cut out, which sealant goes in each one, how deep it goes and how the work gets tested. On buildings finished or resealed before 1980, test the old caulk for PCBs before anyone cuts it. Bid the spec, approve a mock-up, and work building by building in the weather the sealant maker allows. Caulk looks like a cheap fix, and that is the trap. New sealant smeared over old sealant, or gunned into a joint with nothing behind it, peels within a few seasons. Worse, it can cover a flashing problem that keeps soaking the wall. Rules vary by state and by your governing documents, and this guide is general education, not legal advice.

Find the leak before you buy sealant

A stain under a window can come through the sealant joint around the window, through the window itself, past a missing head flashing above it, or from a roof edge two floors up. Recaulking fixes only the first. So the first money goes to diagnosis. ASTM E1105 is the standard field water test: a calibrated spray rack wets the outside while a chamber on the inside pulls a pressure difference, and someone watches the inside face for water. The standard says it can test the joints between a window and the wall around it, not only the window, and that it can be run on a building long after it was finished. Have the consultant test one element at a time so the report says exactly what leaked. The report should sort each leak into sealant, window, flashing or something else, because sealant is not flashing. UFGS 07 92 00, the federal joint sealant specification used on military construction, tells contractors not to use sealant in place of flashing, drainage parts or other weatherproofing, and not to use it to close gaps wider than the installation tolerance. If a bidder proposes caulk to cover a missing flashing, you are buying a patch. If owners own their windows, check the declaration's maintenance chart for who owns the perimeter sealant, and settle it before you bid. Our guide on handling a water leak from common elements into a condo unit covers the damage inside the unit.

Match the sealant to the joint

Exterior joints on a condo or townhome building fall into a few groups: window and door perimeters, expansion and control joints in brick, stucco or concrete, the joints where trim meets siding, and penetrations such as vents, hose bibs and light fixtures. A long expansion joint in a concrete wall moves far more with the seasons than the joint around a dryer vent. ASTM C920 is the specification for elastomeric joint sealants, the silicone, polyurethane and hybrid products used on building exteriors. It sorts them by type (one part or multicomponent), grade (pourable for flat joints, nonsag for walls) and class. The class is the movement the cured sealant can take as a percentage of the joint width, so a Class 25 product handles joints that grow and shrink by 25 percent. The federal spec calls for C920 Type S or M, Grade NS, Class 25 on exterior vertical joints. Write 'ASTM C920, Class 25 or higher, as recommended by the manufacturer for each substrate' into your spec, and let the consultant name the product for each joint type. The Department of Energy's Building America Solution Center recommends silicone or polyurethane over acrylic around windows because they shrink less as they cure. It also says to caulk the head and sides of a window on the outside but leave the sill open to drain. Most silicones will not hold paint, so if your trim gets repainted on a cycle, choose a paintable product or plan to leave the joints unpainted. And a sealant that grips vinyl may not grip painted wood or stucco, so require the manufacturer's written approval for every surface on your buildings.

Test the old caulk before anyone cuts it

On older buildings the sealant coming out can be hazardous. EPA says caulk put in place between 1950 and 1979 may contain as much as 40 percent PCBs, and it recommends testing building materials suspected of containing PCBs and removing them if renovations are planned. The federal spec treats any sealant applied before 1979 as suspect and sends its removal to a separate PCB disposal section. If your buildings were finished or last resealed in that window, have an environmental consultant sample the joints before you bid. A positive result changes the removal method, the disposal cost and who can do the work. Lead is the second question. Caulk that has been painted over takes the paint with it when it is cut out. EPA's Renovation, Repair and Painting rule requires anyone paid to disturb painted surfaces in homes built before 1978 to be certified. On a pre-1978 building with painted joints, ask the consultant whether the job falls under the rule, and require an EPA-certified firm if it does. Our guide on planning an HOA exterior repainting project covers lead-safe work and the owner pamphlet.

Write a spec a director can check

Write each line so a contractor can price it and a director can walk the building and see whether it happened. Removal: cut out all existing sealant and backing from the listed joints. No new sealant over old. The federal spec requires removing existing caulk or sealant before resealing a joint. Preparation: clean each joint to sound, dry material and prime where the manufacturer calls for primer, usually on masonry, concrete and wood. Joint shape: closed-cell backer rod or bond-breaker tape at the back of the joint so the sealant sticks to the two sides and nothing else. Sealant stuck to the back of the joint as well cannot stretch freely, and it tears. Size the bead to the federal table as a starting point: at least 1/4 inch wide and 1/4 inch deep, and on masonry, concrete or wood, no sealant joint wider than 1 inch. Weather: the federal spec allows application only between 40 and 90 degrees F. Write in the manufacturer's limits and no work on wet joints. Mock-up and testing: a sample joint of each type, approved before production starts, then field adhesion tests under ASTM C1521 or the manufacturer's procedure. The federal spec requires removing sealant that fails, retesting it and testing the joints next to it, with a written report of locations and results. Warranty: the manufacturer's material warranty and the installer's workmanship warranty, with their lengths in writing.

Bids, funding and state rules

Ask for a price per building by joint type in linear feet, a unit price for extra footage, and a separate line for PCB or lead handling if testing calls for it. Texas Property Code 209.0052(c) requires an association that plans to contract for services costing more than $50,000 to solicit bids or proposals through a bid process the association sets up. Section 209.003(d) says chapter 209 does not apply to condominiums, so a Texas condo follows its declaration and bylaws. In Florida, Statutes 720.3055 requires competitive bids for HOA contracts above 10 percent of the total annual budget including reserves, and 718.3026 sets the condominium threshold at 5 percent. Neither requires taking the lowest bid. Colorado leaves bidding to your documents and any purchasing policy the board adopted. Florida condos have a funding rule too. The structural integrity reserve study required by Florida Statutes 718.112(2)(g) for buildings three habitable stories or taller must include waterproofing and exterior painting, and windows and exterior doors. Exterior sealant is part of the waterproofing, so it belongs in that study, and a full resealing job should come out of that reserve line, not the operating budget. Our guide on writing an HOA request for proposal covers the site walk and bidder questions.

A timeline and wording to copy

A workable order for a volunteer board: month 1, the consultant's inspection and water tests; month 2, PCB or lead sampling if the building's age calls for it, and the spec; month 3, bids; month 4, contract and mock-up; then production building by building in the months that fit the product's temperature range, with adhesion tests on each building before the crew moves on. Sample motion: 'Motion to approve the contract with [contractor] to remove and replace exterior sealant at Buildings [numbers] per the [consultant] specification dated [date], for $[amount] plus additional joints at the contract unit price up to $[amount], paid from the [waterproofing] reserve, and to authorize [director] to sign.' Sample notice, sent two weeks before each building: 'Crews will replace the exterior caulking at Building D starting Tuesday, October 6, for about [number] working days, weather permitting. Workers will use a lift along the walls, so please move cars from the spaces marked with cones and clear patios and window boxes within three feet of the building by October 5. Keep windows closed while crews work on your unit, and leave new joints alone for the cure time the crew gives you. If a window in your home has leaked, tell [contact] this week so the crew can look at it.'

Mistakes boards make

Hiring a caulking crew before anyone has water tested the leaks. Leaving out backer rod, so the sealant bonds to the back of the joint and splits the first winter. Cutting out 1970s caulk with no PCB test, then finding out mid-job. Skipping the adhesion tests because the joints look fine. And sealing a window sill shut, which traps the water the window was built to drain. When the last building passes, file the consultant's report, the product data, the test results and both warranties in the association's permanent records, and send the reserve study provider the completion date and cost for each building.

Sources

These guides are general education for HOA boards and residents, not legal, tax, or financial advice. Rules vary by state and by your community's governing documents - check with a professional for your situation.

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