LSU AgCenter Housing Specialist
(09/04/20) If your home was damaged by Hurricane Laura, the tremendous work, expense and stress can mean a daunting and difficult ordeal ahead. But it is possible to extract a silver lining from this disaster. If you restore for more than before, you can return to a better home — a stronger, more-resilient, comfortable and healthy home to enjoy with peace of mind.
Take control of your future by making your home more resilient for the next hurricane or flood with these flood-hardy restoration improvements. It’s a great investment to upgrade when replacing damaged materials and equipment, even if your insurance won’t cover the incremental cost.
Making your home flood-hardy and resilient means you can clean up and move back in quickly, with minimal tear-out, replacement, cost and ordeal. It’s not an all-or-nothing approach. Any of the following you can do will reduce future flood damage and the resulting health hazards, ordeal and expenses.
Backflow prevention: Have a licensed plumber install sewage backflow valves in the drain line to protect your home and health. Even minor flash floods in the vicinity can cause sewage back-up.
Damage-resistant materials: Restore with flood-resistant replacement materials, which also tend to be less vulnerable to mold. FEMA evaluates and publishes detailed information about flood damage-resistant materials (see www.fema.gov). Examples include:
Floorings (Note: Types that allow slab/subfloor drying are most advantageous):
— Decorative concrete (overlay or stain), terrazzo, stone, brick.
— Porcelain or ceramic tile (unglazed and unsealed mortar may offer greater slab or subfloor drying capacity).
— Interlocking solid vinyl tiles that don’t need adhesive (can be easily removed to allow slab to dry, then re-installed).
— Solid vinyl tiles or inlaid sheet vinyl with no paper backing and water-proof adhesives and mortars.
— Solid hardwood planks installed to allow easy removal of some or all planks (with water base polyurethane or other vapor-permeable finish).
— Exterior grade plywood subflooring (may swell but can dry and recover).
Interior wall finishes: Paperless (fiberglass mat-faced) gypsum drywall with a moisture-resistant core; removable wainscoting made of plywood, fiber-cement panels or solid wood; removable trim. (Note: Finish with latex paint only, and never use vinyl wallpaper because it can trap moisture in walls and lead to hidden mold.)
Insulations: Closed-cell, high-density spray foam and closed-cell rigid foam boards (extruded polystyrene, or XPS, isocyanate) do not absorb water; semi-rigid mineral fiber insulation boards for exterior sheathing are not ruined by wetting but must be able to drain and dry.
Exterior cladding: Brick veneer; fiber-cement, vinyl, aluminum, some moisture-resistant composite sidings and trim. Be sure to provide a drainage gap behind siding.
Openings: Metal or fiberglass-skin doors with closed-cell foam insulation inside and composite framing; windows with aluminum, fiberglass or vinyl frames (some have metal components that might rust or insulated glass spacers that may leak).
Mechanicals: Elevate appliances, equipment, outlets and switches above the potential flood level. Place water heaters and A/C compressors on sturdy platforms. Wall ovens and front-loading laundry equipment on platforms or drawers could protect them from shallow floods.
Foundations: If you see new or widened slab cracks or diagonal cracks in your home’s walls, hire a qualified professional to evaluate and repair foundations that may require anchors, shoring or underpinning. A variety of techniques are available, so seek an engineered system and installation firm with a solid track record of success. Best are systems that are well connected to the building and have lateral bracing and, ideally, some flex.
— In flood hazard zones, flood vents are required by the National Flood Insurance Program (NFIP) in raised-home and crawl space foundation walls. They must be within 1 foot of the ground to prevent failure from the pressure of rising floodwater and meet placement and area requirements. See FEMA’s Requirements for Flood Openings in Foundation Walls (search in www.fema.gov).
— In this warm, humid climate, insulate raised floors with either closed-cell spray foam insulation between joists under the subfloor or with closed-cell rigid foam boards across the floor joists, taped and sealed airtight. These methods prevent subfloor moisture problems common in air-conditioned homes. (See “Insulating Raised Floors in a Hot Humid Climate” at www.lsuagcenter.com/LaHouse.)
— Relocate any ductwork and equipment out of the crawlspace and above flood risk.
— When possible, the best solution is to elevate the entire house above flood risk. Homeowner flood insurance policies and some communities that receive disaster mitigation grants provide financial resources to elevate homes that have flooded. Check with your local government’s floodplain or emergency management office and your flood insurance policy.
Walls: If walls are open or you will rebuild, consider creating a “washable, drainable, dryable wall” assembly:
— Partially fill wood frame wall cavities with closed-cell spray foam insulation (2-pound density) or rigid XPS foam board cut to fit; or insulate walls with only exterior foam sheathing and leave the wall cavity empty. Leave some empty space in the wall to allow flushing, drainage and drying.
— Install paperless drywall with gaps or gaskets between panels to block wicking across panels.
— Leave gaps at the top and bottom, covered by moldings that can be removed after a flood to allow the wall cavities to be flushed with cleaner then sanitizing rinse, drained and ventilated for drying (with dehumidified air for faster drying).
Learn more about resilient, high-performance home construction and restoration by visiting the LSU AgCenter LaHouse Resource Center website (www.lsuagcenter.com/LaHouse), particularly the Flood Recovery page.
The LaHouse Resource Center on the LSU campus in Baton Rouge is an educational showcase of solutions for the Southern climate and natural hazards. It is temporarily closed due to the pandemic, but you can see tour videos and building system and home improvement videos on its YouTube channel (www.youtube.com/myLaHouse).