Q. We have always wanted to build a home from scratch, and want to plan a house that is modern, fireproof, hurricane-proof and checks all the boxes for a dream house. We have a property to build on, but realize the economy is working against us, since the cost of everything seems to be much higher than when we started our wish list. Someone we know suggested building with concrete block to save money, but the house will be near the bay, and we’re wondering whether it will survive a flood, especially since we know already that we have to have the living floor above the flood height. What do you recommend for building our home? Concrete is what we’ve been seeing, but won’t that be expensive?
A. Concrete is a great choice for building in a flood zone, but not the best material system for saving money over alternate building systems and materials you could choose from, especially for residential construction. The reason why concrete buildings are built, in general, is to meet much more stringent building laws to accommodate a larger number of people, protecting us from fire spread while being very strong and low in maintenance. The code (or written law) is in place to create safe buildings. Fire, wind and flood are very real and ominous threats.
What you have typically seen in flood zone areas is first floor full foundations surrounding the garage and storage areas. Living spaces are required to be above the flood level. You have to be prepared for much more labor-intensive construction above the lowest level if you hope to build out of concrete. Concrete buildings require steel reinforcing rods — tons of them — set into configurations before the concrete is formed and poured.
The concrete is generally formed from wood formwork constructed by carpenters, who must then strip the forms away from the concrete after it has set up and is curing. If this sounds expensive, consider that a wood structure, properly designed and covered in a flood-resistant membrane and cement board, can meet the same regulations for a lot less cost. This is only because one-, two- or three-story structures can still meet the requirements of current law without the excessive strength or flame resistance that larger buildings are required to have.
Concrete block isn’t a better choice. It won’t resist movement like a monolithic, steel-reinforced concrete wall will. Steel wall studs covered with sheets of concrete board, finished with stucco, also stand up very well if anchored correctly, for a lot less cost. You can create the same modern look and avoid the cost of a full concrete structure if you use the wood or steel wall studs above the reinforced-concrete lowest level. Instead of poured-concrete-formed floors, consider wood floors that accommodate insulation better, resist fire and have a sprinkler system that will save the home and contents more economically as well. Good luck!
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