Water Damage in Historic St. Augustine Homes

What makes water damage in an old house different?

The walls work differently. A coquina wall is not a sealed box. The City's flood guidance describes coquina as very porous, with a high rate of water absorption, and says moisture naturally wicks upward through the wall to higher, drier stones, where it evaporates.

That means the wall has to keep breathing. The City says inappropriate maintenance and repairs can alter that process and damage the historic material. A 1988 federal study of the Castillo found the stone highly porous, with damp walls and salt bloom in places. The National Park Service reports that hard Portland-cement mortar in the Castillo's Covered Way wall was speeding up the stone's deterioration.

Modern restoration habits can work against all of this. Seal it, paint it and close it up, and the water stays inside.

Know the wall before anyone dries it

Identify the materials first, since each one changes the plan. Some 40 coquina structures from before 1821 survive in the Town Plan district, the City says, and coquina stayed in use into the early 20th century. Frame houses need a different approach.

The tabby row rests on what the material is, since the sources we read describe its makeup rather than how it dries. The Ximenez-Fatio House describes tabby as a man-made cement of water, lime, sand, ash and crushed oyster shell, and the City's guidelines list tabby and coquina foundations in its Spanish-period styles. We treat it with the same caution as coquina.

Old pine floors, sometimes sold as heart pine, deserve care too. We could not find a public record of which St. Augustine houses have it, so we identify the wood on site instead of assuming. Read whether wet hardwood can be saved before any board comes up.

What counts as dry in a coquina wall?

The usual answer needs adjusting. Our dry standard is the reading of unaffected materials in the same home, but the City says rising damp shows as a darkened band along the base of these buildings. So a coquina wall may never read like a drywall partition, and it was not doing that before the leak either.

Compare like with like. We read the affected wall at set heights, then read an unaffected wall of the same material at the same heights, away from the water. Pin meters are built around wood, so on stone we treat the numbers as comparisons between spots, never as a percentage. The goal is a wall behaving like its neighbors, tracked through daily moisture readings.

Why a reading can rise with no new leak

Salt is the usual reason. The National Park Service describes a whitish tide mark on damp masonry, often 1 to 3 feet above grade and full of salt crystals. It says those salts make the wall more prone to taking up moisture from the surrounding air. So a coquina wall can read higher in a humid week with nothing leaking, and we watch the trend across several visits and do not chase one number.

Does a repair need HARB review?

Often yes, and the answer depends on the district, the work and the material. The Historic Architectural Review Board reviews work under the City's rules, and the City says a Certificate of Appropriateness is required for most work in its five Historic Preservation zoning districts, HP-1 to HP-5. Here is how the City's documents break it down.

• Permits: exterior or interior projects anywhere in the city still need a building permit, and possibly others.
• Guidelines: the 2011 Architectural Guidelines regulate exteriors and do not address interiors.
• Routine repairs: maintenance in the same materials can be pre-approved, but still needs a permit.
• Full demolition: buildings 50 years or older, or anything in HP-1 to HP-5, go to HARB.
• Partial demolition: matching replacements may be approved by staff instead of the board.
• Digging: soil disturbance over 3 inches deep and 100 square feet may need archaeological review.

A house does not have to be in the Town Plan to count. The City treats a building as historic if it is listed, contributes to a National Register district or is a local landmark, and districts include Lincolnville, Abbott Tract, Model Land Company, North City, Nelmar Terrace and Fullerwood Park.

The City has said its guidelines are due for an update, so confirm current rules with Historic Preservation staff. Whoever performs permitted work pulls the permit. Structural repair belongs with a suitable licensed contractor. We scope and sequence the drywall and paint put-back, and the same goes for flooring.

Drying rules we follow in older homes

Slow and measured wins here. The National Park Service's guidance on moisture in historic buildings puts diagnosis ahead of treatment, and EPA advises dehumidifiers, gentle heat and fans for wet wood. We work the same way.

1. Photograph every finish before moving anything.
2. Remove the water first, then find out how it got in.
3. Run structural drying with LGR dehumidifiers, sized and watched, not maxed out.
4. Pull non-historic finishes that trap moisture, as the City's guidance suggests.
5. Stop and ask before removing anything original.
6. Keep pressure washers off masonry, which the City's guidelines rule out.
7. Leave sealers, cement patches and latex paint out of the wall.

The Park Service gives the reason for that last rule. A waterproof coating on the inside of a damp wall, such as cement parging or vinyl wall covering, does not stop the water. It pushes the capillary rise higher up the wall.

When the mold clock meets a slow answer

These two pressures collide, and we would rather say so. EPA wants wet materials dry within 24 to 48 hours, and City staff may not answer a question about original plaster in that time. So we split the job. Water comes out now and drying starts now. Modern finishes trapping moisture can go. Anything that may be original gets photographed and stays until staff or a preservation specialist weighs in. If nobody can say whether it is original, we treat it as original.

The other honest limit is time. The Park Service says broken pipes should be fixed promptly, but a complicated moisture problem may take several months, or up to four seasons, of monitoring to diagnose. We can finish the emergency without finishing that question. A band of rising damp that was there before the leak may still be there after we leave, and slower drying adds equipment days you should expect to see on the estimate.

If river water is the cause, it is Category 3 water, and our flood and storm damage rules apply alongside everything above. Homes in St. Augustine Beach are in a separate city, so HP zoning there is not the question, but check that city's building office before you assume.

Move fast on water, slow on original material

That is the whole decision in an old house. Get the water out and the air drying today, then take your time over anything that cannot be replaced.

Found water in an older home? Call us before anyone starts cutting. We will read the walls, tell you what we see and what we do not know, and give you an estimate at no charge.