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A Guide to Building in Southwest Florida


An Outline for energy efficiency and sustainable building practices

By Rob Andrys A.I.A.




Building strategies  


Building Systems  

A.    Roof System

B.    Wall Systems

C.    Floor Systems  

D.    Window Systems

E.    Mechanical Systems  

F.     Lighting Systems  

G.    Plumbing Systems

H.    Interior finishes

Energy Efficiency  




Building in Southwest Florida in unlike building anywhere else in the continental United States.  We live in the Subtropics where we average 50” of rainfall per year, rarely use heat and cool our homes most of the year. 


More important than cooling the home is removing the humidity that damages the interior finishes, propagates mold and mildew, leading to indoor health problems.  Removing this moisture when the outside humidity is above 80% requires special consideration in the design process.  By keeping the moisture out of the building through its design, the air conditioner can be smaller and run less often.

Other considerations of living in the subtropics are the damaging effects of hurricane winds, flooding, extreme ultraviolet sunrays, wood eating insects and dry rot.


The design and selection of a building’s materials and systems must ensure durability, low maintenance, and optimize indoor air quality, without compromising the planet’s future.  

Building strategies

The overriding strategy for building in Southwest Florida is to: maintain a dry interior; keep the rain away from your walls; hurricane strap the structure; stop the termites from making your home their next dinner; and become allies with the natural elements instead of fighting them.


Building Systems

The following are suggested building component systems that, when combined in a thoughtful design, allows your home to be energy efficient, healthy and have a long life.


A.        Roof System


The roof is the second most important component of your building (The first being the footing and structural frame the roof sits on).

Rainfall striking the roof should be managed, that is, gutters and downspouts are important ways of keeping water away from walls, thus reducing dry rot and insect invasion.

Choose roofing that is in your budget that provides the longest life, the easiest maintenance and serviceability.  Concrete tile roofs are the most durable and energy efficient, followed by white standing seam metal roofing, and, lastly shingle roofs.

The color of a roof is directly related to how much it will cost to cool the building.  The closer to white, the more cost saving the building.


Roof Penetrations

All penetrations of the roof are potential leaks.  Keep penetrations to a minimum, and personally inspect all penetration flashings before being covered up by the roofing.  If you plan on adding a component in the future which requires roof penetrations, (such as a solar heater), install the lead sleeve or flashed opening during the initial construction.

If solar panels will be added in the future (most probably), make accommodations on the south side of the building.  Brace and/or block the trusses affected, provide penetration boots.  Do research in planning ahead for the inclusion of these panels. 


Hurricane considerations

Whatever roof you pick, consider that this is hurricane country, and should be tied down to the highest degree possible.  Tile roofs should be screwed down with stainless steel screws, metal roofing should have the seams mechanically adhered and the fasteners placed under the metal, not penetrating it.  Shingles (if used) should be the laminated type with the first row set securely in mastic.  The plywood sheathing should be secured with twist nails or screws.   Finally, the best shape for a roof is a hip roof with an average slope.


Radiant Barriers

Radiant barriers have proven to be very helpful in reducing the energy load on a building.  The newest radiant barriers are now spray applied to the bottom of roof sheathing; this allows complete coverage, ease of installation and no damage to the barrier during construction.  The inclusion of a radiant barrier is dependent on the type of roof you select.


Sealed Attic Space

Research from the Florida Solar Energy Center and Building Sciences corporation has conclusively shown that an un-vented, sealed attic space with the insulation placed below the roof sheathing is the most cost effective and healthy way of building in Florida.  By sealing the attic, the air conditioning unit runs less because it no longer draws the limitless supply of humid air through the gypsum board ceiling or the holes in the light fixtures into the house.  Furthermore, by having a warm, relatively dry attic space rather than a hot, humid attic, it does not allow the mold and mildew to accumulate on the gypsum board ceiling. It is also more forgiving in the possibility of a/c duct leakage.


B.        Wall Systems

Walls built in SW Florida must resist hurricanes, termites and keep the moisture from entering into the building.

All walls leak moisture through them.  Walls must be designed to have a drainage plane from top to bottom to direct this moisture down and to the exterior.

Wood walls should be discouraged for the above reasons. (Cypress and heart pine woods that historically had been used successfully are no longer commercially available.)

Metal stud wall systems are available and solve the termite problem, but must be engineered to resist hurricane winds and will rust if exposed to water seeping into the walls.

Masonry walls or variations of them have preformed excellently when properly designed and installed.  They are much stronger than wood or metal walls, they do not burn or rot, and are not damaged by wood eating insects.  The following are various types of masonry wall systems currently in use and commercially available.

Hollow Concrete Block-traditional.   The traditional SW Florida wall system consisted of concrete block covered with stucco on the outside surface.  On the inside ¾” pressure treated furring strips are fastened to the block, ¾” fiberglass batt or rigid foam board is placed between the furring and then covered with ½” gypsum board. Concrete blocks are readily available and made from local resources.  

Advantages: Cheapest way of building a wall.

Disadvantages:  Allows moisture to enter through the wall, has minimal insulation value, and in areas exposed to the sun the block heats up and radiates heat into the building even after the sun no longer is striking the wall.  The ¾” furring requires that the concrete block be cut open where electrical outlets and switches are located.  This allows moisture an easier way to migrate into the building, especially if the concrete block is also penetrated on the outside for the same reason.

Hollow Concrete Block-updated.   The updated method of using concrete block is to stucco the outside surface. On the inside 1 ½” furring strips are fastened to the block, then the walls and furring are sprayed with a water-based semi-permeable coating, allowing the block to dry out somewhat, but slowing down the transfer of water vapor into the home.  Between the furring, 1 ½” semi-rigid un-faced fiberglass boards are installed and covered with ½” gypsum board.

Advantages: Varies only slightly from the traditional method, thus construction prices are low, moisture barrier is continuous, and fills all holes and cracks.  The 1 ½” furring allows electrical outlets and switches to be placed within the furring space so that cutting the concrete block is not required.

Disadvantages:   In areas exposed to the sun, the block heats up and radiates heat into the building even after the sun no longer is striking the wall.  Requires poured concrete tie beam at top of walls and large openings.  Concrete lintels are needed above windows and doors.  Allows areas for insects to live in the hollow voids.


c.  Foam Insulated Concrete wall system (FIC).  This system uses hollow expanded polystyrene blocks or other insulating materials that are used as concrete forms.  Steel reinforcing is added and ready mix concrete is then pumped into the hollow cavities creating a solid concrete wall with insulation on both sides.  The outside surface can be stuccoed, sided, or a brick veneer installed.  Depending on the manufacturer, the inside surface is ready to receive gypsum board, or must have additional wood-furring strips fasten to the forms for attaching the gypsum board.  

Advantages: Much stronger than hollow concrete block walls.  In areas exposed to the sun, the block does not heat up and radiate heat into the building because the insulation is on the exterior.  Does not require poured concrete tie-beams or lintels. Lower infiltration of air because of solid concrete. The foam can be cut to allow electrical outlets and switches to be placed within the wall system.  Can be quicker to install than hollow concrete block or traditional poured-in-place concrete walls.  

Disadvantages:    More expensive to install as a system than hollow concrete block.  The moisture barrier must be placed on the outside of the wall by means of an electrometric paint that needs to be repainted every 5-7 years. 


d.   Aerated Concrete blocks.    This system uses solid aerated concrete blocks that are ‘glued’ together in the same fashion that a typical concrete block wall is grouted together. The outside can then be stuccoed, sided, or a brick veneer applied.  On the inside of the wall a water based semi-permeable coating is spray applied, then a thin plaster coating is directly troweled onto the aerated block. 

Advantages: Higher ‘R’ value than hollow concrete block walls, or a FIC system.  In areas exposed to the sun, the block does not heat up and radiate heat into the building.  Low infiltration of air into the house because of solid construction. The aerated concrete can be cut with a conventional saw to allow electrical outlets and switches to be placed within the wall system.  Can be quicker to install than hollow concrete block.

Disadvantages:    More expensive to install as a system than hollow concrete block. Requires poured concrete tie beam at top of walls and large openings.  Requires larger footings for ‘dead weight’ to resist hurricane wind loads.


C.        Floor Systems

Floor systems built in SW Florida began with raised wood floors built above ground to allow air circulation under the house to cool it and keep the house above periodic flooding and away from termites. Today we raise the floor for many of the same reasons, except moist air is no longer desired under the floor plane.  An un-vented crawl space is desired for the same reasons an un-vented attic is advocated.  

Concrete slabs can be poured directly on the ground and the home built directly on the slab.  It is recommended that the height of the floor be higher than your road or flood stage.  

If the home is desired to be raised above grade, a footing is poured and a stem foundation wall is built up to the desired height of the floor slab.  The inside area of the stem wall is then filled with sand, compacted, the slab poured, and the remainder of the walls constructed.

Raised wood floors are still in use usually when higher elevations are desired for parking below or for flood elevation requirements. The structure is usually pressure treated wood, a system that is not usually viewed as a permanent foundation.

The floor system must resist hurricanes, termites, and keep moisture and radon gas from entering the building. 


D.        Window Systems


Window systems must resist hurricanes, termites and keep the rain and moisture from entering into the building.  

Traditional wood windows are beautiful but do not hold up in Florida, as evidenced by their failure in older homes. Newer aluminum clad windows have solved much of this problem.

Aluminum frame windows are popular because of their durability and ease of maintenance.  Since we do not have the long duration of cold weather that creates large temperature differences between indoors and outdoors, thermal conductivity and the resulting condensation problems are viewed as minor deficiencies in the selection of an aluminum window. 

Vinyl windows solve the thermal conductivity losses and corrosion problems associated with aluminum windows.  They are becoming more durable with the advancements of UV blocks that stop the vinyl from becoming brittle.  However, field-testing is still years away from a final answer on durability.  Solid vinyl windows have also experienced problems with losing their shape as the horizontal dimension has increased.

Vinyl clad wood windows have the same dependence on a good UV block, but they also tend to keep their shape better than an all-vinyl windows and have the advantage of a wood look on the inside and no thermal conductance loss.



Window glazing is typically only single pane in SW Florida, again due to the low number of days where there is a large temperature difference between indoors and outdoors.

The glazing is usually clear or slightly tinted.  If there is no physical solar control on the east or west sides of the building such as awnings or trees, a reflective, tinted or spectrally selective glazing is highly recommended.  Controlling the solar heat gain through windows is important not just for cooling concerns, but for damage to the home’s interior finish. 


Skylight and Light tubes

Skylights deliver expansive amounts of daylight into a space by virtue of their location high in the ceiling and positioning to the sky.   Along with “free” light, they permit a view to the sky, but can also become noisy in a heavy rain.  There are disadvantages: they have a history of leakage problems, it is imperative they be covered in a hurricane, and the day light can be hard to control contributing to large amounts of solar heat gain and damage to interior finishes of homes.

Light tubes require smaller roof penetrations, deliver smaller but more controlled daylight to the space, but do not give a view to the sky.  


E.        Mechanical Systems

Mechanical systems in SW Florida are primarily used for cooling and dehumidifying.  They usually come with an electric heat strip that tempers the air during our days of cold weather. Removing humidity is the top priority from an indoor air quality assessment.  Second is to make sure the building is under a positive pressure; the mechanical system should not create a building that sucks moisture into the house.  If the system is not designed correctly, you can have a cool house, but still have humidity problems from a bad design or leaky ductwork.  Humidity allows molds to grow in the ductwork, carpet, drapes, etc.; molds are the number one air pollution in a home.

Along with the issue of humidity, there is the need for correct ventilation.  As the building is ‘tightened’ up and allows less air to infiltrate through leaky doors, windows and cracks in the wall, the indoor air becomes stale and polluted by our everyday activities.  The air inside must be exchanged with fresh outdoor air, but that air is usually very humid and must be conditioned before entering the building.


The most popular systems and most affordable systems are Direct EXchange air conditioning units, (DX units).  A DX unit is comprised of two components, an indoor air handler and an outdoor condensing unit.  The indoor unit removes heat from the home and in the process condenses humidity on the coil that collects in a pan and runs outside.  The outdoor unit condenses the refrigerant gas by drawing air across the coils, expelling the heat to the outside air.  When the ambient outside air is hot and humid it takes much longer to remove the heat and more coils are needed, thus bigger outdoor units are also more efficient.  The more heat that can be removed from the refrigerant gas, the more efficient the system runs.  That is why water is used on large commercial systems, because it usually has a lower ambient temperature and can remove heat easier. 

Variable speed A/C units are an excellent way of removing humidity using a modified DX machine.  The inside air handler has a variable speed fan that start up at slow speed and gradually comes up to full speed.  This allows for the coils to become very cold at first, then as the fan speeds up, the coil is warmed to normal operating temperature.  Thus more moisture condensates on the coil and is subsequently removed from the home than a conventional DX system.

New systems include heat pipe technology, heat pumps and combinations of DX and dehumidifying units.  Heat pipe technology has the most promise since it removes more humidity using the same amount of energy as a DX system, this is especially important if higher levels of fresh air and, or low humidity levels are desired. 

The placement of the ducting should occur within the air-conditioned part of the house.  It has been estimated that duct leakage accounts for 1/3 of the total Florida residential cooling and heating consumption.  To reduce the amount of dust and mold in the ductwork, metal or plastic-lined ducts should be used.  Ductwork with fiberglass exposed to the air stream should be avoided.


Air to air heat exchangers or heat recovery units are used to remove humidity from incoming air and cool it down by exchanging the heat from the outgoing stale but conditioned air.  These units are not as popular here as in colder climates where the temperature difference is more extreme, however studies are now showing how important is it to pressurize a building in the humid south regions.  If a home does have air leaks then moist humid air is not drawn through that opening in to the building.  This creates a spot where the building is moist and causes mold to grow and a place for termites to feast.

Windows should be operable to allow natural ventilation.

Paddle fans are still one of the best ways to circulate air efficiently.  New high efficiency fans shaped like air plane propellers are now available.

Water Heating

In SW Florida it is just plain wasteful to heat water using electricity.  It is estimated that in a home containing 4 or more people that 30% of the average electrical bill is spent on heating water. Solar panels are most effective way to heat water, the payback is immediate when amortized over the life of the mortgage.  The other method of heating water is to use a heat exchanger in conjunction with the air conditioning unit.  However, this heats water only when you are using the air conditioner.


F.         Lighting Systems

Efficient lighting systems employ as much fluorescent lighting fixtures as possible.  Compact fluorescent technology now allows fluorescent lighting to be used in regular incandescent fixtures.  These compacts use 60% less electricity and add 30% less heat load to the A/C equipment. This constitutes tremendous comparable cost savings. Further advancements in fluorescent now add a full spectrum light source, eliminating the garish yellow hue.  

Halogen light bulbs should be used where brighter light levels or dimmable lighting is desired, rather than incandescent bulbs due to their higher efficiency. 

Recessed can lights should be insulated and used sparingly considering you are punching a hole in your ceiling, allowing attic air to enter your house.


G.        Plumbing Systems


Grey water treatment systems are relatively new to the market in SW Florida, but have been fulfilling water conservation needs elsewhere for quite some time.  The use of domestic drinking water for irrigation of plants is expensive and wasteful.  These systems reuse water that is put down the drain of tubs and lavatory sinks of the home. Efficient use of water saves money and allows the use of irrigation water during the “water restriction” dry months of the year.

Water catchment systems utilize collecting rainwater from the roof, filtering it, storing it in underground cisterns, and then pumping it out as irrigation water when needed.


Drinking water

Drinking water that is usually purchased in a supermarket is not only costly and wasteful, but also inconvenient.  The manufacturing of pure, clean water at the home without excessive amounts of water needed to back flush the unit is now available.  The purity of the initial water source will determine how many and what kinds of components are necessary.

Swimming Pool

The typical chlorine systems used in most homes are now being questioned as to its healthiness.  New bromide systems are less expensive to operate and maintain, have less health risks for the users, and are less corrosive to the various metals used in the pool system, thus prolonging their life.


H.        Interior finishes

Wall Coverings

The most common and dangerously unhealthy practice is to install vinyl wall coverings on an exterior wall.  This creates a vapor barrier on the wrong side of the wall, allowing moisture and fungi to accumulate on the backside of the vinyl.

Oil based paint have the same results as vinyl wallpaper on an exterior wall, use latex paint. 

Oil based paints release VOCs that are not whisked away magically after they are applied.  They are absorbed by other soft materials in the house and then released slowly over time, making the air unhealthy.  Sherwin-Williams offers no VOC paints.

Natural fiber wall coverings should not be used in rooms with frequent exposure to high humidity; the fibers become a breeding ground for mold.

Floor Coverings

Carpets should be used sparingly, as they can become breeding a ground for mold if not cleaned often with a powerful vacuum cleaner.  Dirt is the medium that molds grow in, not carpet, but dirt can hide better in carpet than tile.

There are more sustainable products on the market than real wood flooring such as bamboo, cork and linoleum.


This list will be added to, amended and edited in coming months.  If you have any comments, please address them to Rob Andrys Architects, at AndrysR@ix.netcom.com



Energy Efficiency

Priorities for energy efficiency for new residential construction in Florida.

                                                By D. Parker/R. Vieira, Florida Solar Energy Center


                                                The options are listed in order of importance:


Proper window orientation

Windows should be maximized on North and South walls and minimized on east and particularly on the west and northwest.

Window shading.

By use of exterior shading devises such as porches, awning shutters, trellises.  This reduces cooling costs while preserving daylight.  Trees can also be very effective and increase a homes value as they grow.

Light colored surfaces on exterior.

Low cost to implement yet has high energy efficiency.

Low energy use appliances and lighting.

Keeping internal heat generated loads low will save on A/C costs.  An efficient refrigerator is particularly important along with using as much fluorescent lamps as possible.

High SEER A/C systems

Use at least a 14 SEER with a variable speed indoor fan unit.  Unit should be sized using “Manual J” (a/c design manual) with the 97.5% summer design temperature for the location and a 75 degree indoor temperature.

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