A New Orleans French Quarter Construction Project
In the Autumn of 2006 we were asked by a client and a friend of ours to help with a phased New Orleans renovation of an incredible French Quarter townhouse on Royal Street. The friend had been a repeat customer of Hal Collums Construction over the years. The owner, born and raised in New Orleans, was a successful oil industry business owner now living in Houston. He and his wife had purchased their French quarter dream home and were ready to begin renovating it to match their tastes.
The phases included:
1. Structural Repair
a) Inspection and water testing
b) Window remediation plan/execution
c) Flat roof remediation plan/execution
d) Close cornice remediation plan/execution
e) Re-pointing exterior walls where water is indicated
f) Removal and replacement of rotten fascia, railing, newel posts at both balconies
g) Emergency remediation of water intrusion at masonry walls
a) Elimination of rustic exposed beams on 2nd floor service quarter
b) New shutters
c) New kitchen
d) Redesigned laundry room
e) New wood floor on 1st floor
f) Re-finish wood stair steps
g) Re-painting of interior
h) Repainting of exterior front and courtyard walls and millwork
i) Master Bath vanity design challenge/solution
This first blog post in a series will address phases 1a, 1b, 1c, and 1d:
Initially we needed to investigate suspect areas of water intrusion. The building inspection indicated several suspect areas where water was entering the structure. Infrared inspection had identified moisture around several windows, around a flat roof where HVAC equipment was installed, an interior common wall on both floors of the service quarter, and a rear service quarter balcony.
This project gave us an opportunity to enhance old world building details with modern materials
Visual inspection confirmed deteriorated leaking windows, suspect flat roof details, suspect rear balcony flashing, water intrusion in the rear service quarter balcony structure and rotten railing, fascia and columns on both balconies. Follow up physical inspection including destructive testing explained most of the problems and guided our repair and restoration plan.
The wood bucks embedded in the windows were completely obliterated by chronic water intrusion from brick borne moisture entering through washed out mortar and wicking up from the spread footings. Reliable moisture invited in termites and the destruction of the wood bucks was complete long before being revealed by our inspections. Our solution involved removal and replacement of the wood bucks with matching pressure treated wood, replacement of all needed window components, re-pointing of surrounding masonry, back-priming all new and existing wood, re-fitting and reinstallation of restored windows, and properly detailed caulked expansion joints. Replacement of the wood buck gave us an opportunity to enhance an old world building detail with modern materials by using vinyl shower liner to provide a tough permanent moisture barrier.
The flat roof was an infill roof added during an later remodel, probably in the early 1900’s. Initially a metal flat seam roof, it had been reroofed with a torch-down roof in the last 30 years. Our solution was to reroof with redesigned flashing details and a modified bitumen single ply roof. Being a small area prone to frequent service traffic, It was worth reroofing the whole area with a modern roofing material more suited for the demands on it. Modern glue seam materials are easy to use and economical. Most important they are a durable, reliable low slope roof surface when properly installed.
The courtyard balcony moisture intrusion problem was not clearly apparent. We suspected the flashing at the brick wall to balcony deck was leaking. Moisture meter readings on the interior sheetrock indicating a horizontal line of moisture corresponding to the exterior balcony flashing seemed to confirm our suspicion.
Before we planned a remediation strategy based on solving the most apparent problem, we needed to be sure we repaired all the problems. Oftentimes good technicians make mistakes by repairing the most obvious problems. The flashing leak was probably the major leak but other water intrusion possibilities existed. The window sills and door thresholds were weathered and could be leaking into the wall. The exterior masonry wall was soft red brick with original mortar, having a high probability of moisture intrusion through the masonry wall. Another possibility was moisture wicking up from the spread footings.
Most French Quarter masonry buildings are built on a footing that spreads out as it descends into the soil. Spreading the load out helps support the weight of the wall and building. The original builder would dig a trench to go below the surface a sufficient
distance to reach a sandy soil strata, usually no more than 3 to 5 foot. The first course of brick could be 3 to 6 times wider than the thickness of the desired wall.
Early builders used a course of slate as a “wick stop” with some success, but rising dampness must always be considered when renovating a spread footing building.
Each subsequent course would step in slightly until the wall reached ground level where it would only be as wide as the finished brick wall. This allowed early builders to build impressive structures on our soft soils but it also allowed ground moisture to wick up into the structure through the masonry foundations. Early builders used a course of slate as a “wick stop” with some success, but rising dampness must always be considered when renovating a spread footing building.
With several possible reasons for elevated interior moisture we decided a controlled testing protocol would be appropriate before we could formulate a comprehensive remediation plan. This involves strategic placement of water tests with controlled timing and scientific recording of data to prove (or disprove) our hypothesis of moisture entry. Testing always needs to start at a low point and control the moisture delivery. We began by recording a grid of moisture readings on the interior sheetrock wall on squares of blue painter tape. The moisture reading is our baseline and we look for increases in the moisture content as it is tested to help us graph and see the moisture intrusion occurring during our test. We open some areas in the interior sheetrock and the balcony closed cornice structure for visual observation during our testing. By beginning low and moving our testing up in levels at predetermined time intervals, we can easily see and record leaks and moisture wicking as it occurs. The moisture content is a clear indicator of water intrusion easily mapped across a wall to visualize the mechanics of the water intrusion.
We decided a controlled testing protocol would be appropriate before we could formulate a comprehensive remediation plan. This involves strategic placement of water tests with controlled timing and scientific recording of data.
By beginning at the lowest possible water entry level and moving up in timed stages, gravity will not contaminate our results allowing us to do comprehensive, conclusive testing usually the same day. Our testing on the rear balcony service quarter wall showed us that the balcony flashing was indeed leaking, but we were also receiving moisture from the masonry wall and from around the windows.
The water testing did show rising damp wicking up from the footings was not a problem on this wall. Our final remediation plan included new porch flashing, re-pointing the exterior masonry wall, replacement of damaged window sill, and new caulking with backer rod around window.
The closed cornice balcony structure of the rear service quarter had signs of chronic moisture intrusion, a common occurrence due to a flaw in a closed cornice detail. The closed cornice balcony has an enclosed soffit on the underside of the deck to hide the structure. It is usually highly decorative millwork with a painted finish.
Historically the deck surface was air dried tongue and groove heart pine. The tongue and groove board edges were liberally primed with high lead content deck paint. It was hand nailed by craftsmen with the final blow delivered to both set the nail in the tongue, but also drive the still tacky painted tongue tighter into the receiving groove.
Several coats of leaded deck paint, combined with a correctly detailed and installed flashing provided a fairly reliable watertight deck. This barrier was dependent on good maintenance in the form of regular repainting and re-caulking because the integrity of the wood deck barrier is dependent on the seal between the multiple linear tongue and groove joints.
As the wood deck moves with the changing New Orleans climate the barrier is dependent on the paint seal on the deck and between the wood. With age the oils breakdown, the paint looses its bond, and once the seal is broken, the moisture begins damaging the structure.
Even the original builder of a historic closed cornice using more stable old-growth wood and durable lead based paint still needed apply regular maintenance to prevent decay. Advanced maintenance requirements mean that few original closed cornice balcony structures survive intact today. Rebuilding authentic detailed closed cornice balcony soffits with modern materials is still a challenge and still requires careful paint and caulk maintenance.
Modern replacement decking that satisfies historic material requirements (such as the Vieux Carre and HDLC districts) require a replacement wood deck.
Tongue and groove decking should never be installed if it has more than 12% moisture content
Modern commercially available exterior wood is usually pressure treated wood. Cut from new growth southern yellow pine, it is kiln dried, then pressure injected with a waterborne preservative chemical, and either air dried or kiln dried again. The resulting decking is often job delivered wet and needs to be further dried before installation (you should never install tongue and groove decking with more than 12% moisture content).
The next concern with modern material is that lead free paint does not have the body or the bonding of some historic paints. The recommended paint is porch and deck enamel. Pressure treated decking must be edge-primed with the selected color P&D enamel thinned 50% with mineral spirits before it is installed. Once properly nailed and top-coat painted and correctly flashed, (with an adequate fall away from the building built in) the deck is adequately water tight to keep moisture out of the assembly.
All finish porch material should be fabricated from weather resistant materials (pressure treated wood, hardi-board, or preferably Spanish cedar if being milled). All wood components in the closed cornice assembly should be liberally back-primed before assembly to further protect against wood rot. With proper details, good execution and proper paint and caulk maintenance a closed cornice soffit can last a lifetime.