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Panel Location

Panel Location
Connect Panels
Secure Panels
Solar-loop Piping
Connect to Pool Equip.
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1. determine Panel location

The first step in installing a system is to determine where they will go.  This is predicated on proper system design (see system design):

  • Proper panel sizing to pool surface area
    • 50-100% of pool's surface area depending on location, climate, desired season, etc.  Every situation is different so contact us with your information and we will assist you design your system.
  • Panel orientation(s)
    • Preferably between SE and W--SW is best usually.
  • Mounting surface

Mounting Surface considerations

  • ROOF OR RACK.  Installing FAFCO solar panels is a fairly straight-forward process.  The panels connect together the same way in all situations but how they are mounted is directly dependent on what they are mounted to; whether on a rack or a roof and what type of roof.  Racks can either be roof or ground mounted (see Panel Racks).  You can also build your own racks out of wood or strut channel, etc., but durability and/or aesthetics should be considered.  Remember, solar pool systems can last well over 20 years so the structure they are mounted to should too. 
    • For all surfaces, if potential abrasion of the underside of the panels is possible, put corrugated sheets under panels for protection. 
      • 26" wide sheets in 8, 10, or 12 foot lengths are usually available at most building suppliers like Home Depot.


  • ROOF OBSTRUCTIONS will determine panel layout
    • Remember panel headers are actually 51" wide (figure 52" to be safe) and 8, 10, or 12 feet long.  Leave at least 3" top and bottom to secure mounting hardware.
    • Plumbing and/or roof vents, skylights, chimneys, etc. can interfere with panel location.
      • It's OK to put gaps between panels to go around such items using Sch. 40 PVC pipe
      • Also see "Plumbing Panels Together" later in this installation instructions.
      • Use FAFCO CPVC female adapters (#5381) at all panel coupler / PVC connection
        • Every gap or split will require two more rubber couplers, four s.s. clamps, four female adapters and maybe more tie down cleats depending on width of split.


  • PITCH OF THE ROOF can be an issue at the extremes (i.e. too shallow or too steep). 
    • FAFCO panels should not be installed on a flat surface anyplace where there is the possibility of freezing conditions.  The panels will not drain completely laying flat.  Pitch must be greater than 6 degrees or a 1.25:12 slope (1.25' vertical rise per 12' horizontal distance)
      • Don't rely on using positive air pressure to evacuate any water from flat installations.
      • Thus, flat roof installations are out unless in warm climates like Hawaii.  Otherwise it would be necessary to build racks to pitch panels at least 6o.  See information on building either a steel strut or wooden panel racks (Panel Racks)
    • EPDM rubber panels can often be safely installed on flat roofs in some cooler climate situations because they can usually expand enough to avoid damage.
      • We offer a rubber system for these situations only, however, long-term durability of these products is an concern.  EPDM tends to degrade from water chemistry.
    • Steep roofs (>6:12) can be a problem too--safety needs to be prime objective in this case.
      • The further you get away from a direct southerly orientation, the more steeper pitches reduce performance.  Add surface area in these cases.


  • TYPE OF ROOF is a major issue with regards to how the panels are mounted.  The following is a very brief description of some of the most common roofs and the mounting procedure for each:
    • General roof installation issues for all roof types:
      • Panel hold-down cleats should secure to the sub-roof.
        • Panels do NOT need to secure to roof rafters unless strut channel is used.
      • Use 1/4" hex head lag bolts of whatever length is needed per roof type.
        • Use galvanized or stainless bolts as needed depending on climate and availability.
        • Bolt should penetrate through the sub-roof about 1/2" for best hold.
          • Be careful of what's under sub-roof (attic, vaulted ceiling, open beam ceiling)
          • See Sub-roof section below.
        • Be careful not to overtighten bolts that could strip sub-roof and not hold well.
      • SEAL ALL ROOF PENETRATIONS.  Be sure to seal all roof penetrations thoroughly with a good quality exterior asphalt/plastic-based sealant like Henry's 208 (only on asphalt roofs) or polyurethane sealants like Henry's 900, Sikaflex or Vulcumseal generally available at Home Depot.  Avoid silicone!  Use sealants in a tube that fits into standard caulking gun.  Remember, properly sealing the roof is the best insurance from future roof leaks.  When in doubt, use more sealant.  Use enough so excess squeezes around edge of tie-down cleats.
    • Asphalt-based roofing material
      • Comes in shingle or rolled configuration
      • Usually installed over a plywood sub-roof
      • Easiest roof for mounting solar panels
      • Requires no special attention if at least modestly pitched; >1.25:12
      • Use minimum 1/4" x 2" lag bolt to secure "tie-down cleats" into and through plywood
        • Also be sure of the roof thickness since these roofs are often reinstalled over existing roofing.  This would determine need for longer lag bolts.
    • Wood cedar shake shingle
      • Usually installed over felt and 1x6" sheathing boards @ ~1' o.c.
      • Watch for nail heads or staples pushing out of roof.  Re-nail or remove.
      • Clear any sharp objects off roof including branches and sticks
      • Necessary to pre-drill shake only (but not sheathing boards) wherever bolts need to go to avoid splitting shingle.  Use 1/4" or bigger bit for 1/4" bolts.
      • Note and seal all split shakes or use metal flashing underneath.  It is actually a good idea to put metal flashing at all roof penetrations.
      • Use minimum 1/4" x 3 1/2" lags in most cases.
      • Use plenty of sealant since it is cheap insurance against roof leaks. 
        • Squirt sealant down hole of pre-drilled shingle before lagging
      • Another option is to use strut channel to minimize penetrations (see below).
    • Tile -- concrete, clay, or composite.
      • Usually over plywood or sheathing boards depending on age of roof
      • Some tile are difficult to walk on without causing damage, especially clay
        • When walking on roof, face up-slope of roof and put weight (your heel) on "toe" (front edge) of tile course where the courses overlap so it is stronger
      • Recommend strut channel to minimize penetrations (see below)
      • Need to pre-drill concrete tile with masonry bit.
      • Clay tile probably needs to be removed and replaced with asphalt roofing where panels need to go. 
        • Run asphalt roof from above panel location to eave.
        • Once panels are installed, tile can be put back around panels as a facade.
    • Metal (steel or aluminum)
      • Usually over sheathing boards or plywood.
      • Many designs and profiles. 
      • Screw head location is critical to installation methods
        • To protect panel from screw heads abrading the underside of panels, use corrugated sheets under panels or exchange hex head screws with pan heads or cover screw heads with dollop of sililcon and let it set-up before installation.
      • Can often mount directly to roof but, because of varied contour, strut channel is recommended on many profiles
        • Contact us with picture and/or cross-sectional drawing of roof to determine best method
      • Standing-seam roofs require special consideration
        • Special S-5 clamps are available to attach to seam and avoid any need to penetrate roof.
    • Pitch and gravel (or tar and gravel). 
      • No longer common, thankfully
      • Difficult to seal to due the granular nature of the gravel
        • Gravel must be cleared wherever tie-down cleat connections are made to roof
      • Use corrugated sheets under panels to protect them from abrasion from gravel
      • Recommend re-roofing with another roof type or contact us for more detail mounting instructions.
  • SUB-ROOFS are important too.  This is the structure to which the roofing is secured.  If you have an attic area under the panel location, you can always check out the type of sub-roof you have.  You shouldn't need to get up into the attic to mount panels to roof unless using racks.
    • This is usually plywood or sheathing boards
    • What's under the sub-roof is most critical since you don't want lag bolts sticking through your ceiling.


  • CEILING TYPE.  You need to determine if you have standard flat ceiling with attic above, vaulted, or open beam ceilings.  All these site issues need to be addressed before mounting procedure is determined. 
    • Open beam ceiling probably should use strut channel to secure to beams rather than the tongue and groove (T&G) boards across them, especially when only 1" thick. 
    • You don't want to use lag bolts that can potentially penetrate through ceiling.

What is strut channel? 

Strut channel is steel and comes in a low profile steel design (roughly 13/16" x 1 5/8") or high profile that is 1 5/8" square.  It goes by many names but is readily available from electrical wholesale outlets, Home Depots (galvanized or zinc-chromate gold) or Lowe's (zinc chromate).  We recommend the chromate type since it is more durable in adverse climates like Hawaii or coastal situations but galvanized is usually fine too.  It cost about $1.20/foot.

  • Strong and durable with rounded edges
  • Multi-slotted for ease of mounting as needed to roof rafters or rack supports
    • Slots are large so use fender washer when bolting together
  • Allows for fewer roof penetrations on tile and metal roofs or with open beam ceilings
  • Uses strut-nuts that lock onto strut channel--very cool
    • strut nuts come with various threaded hole sizes.  Use 1/4" since our cleats have only a 1/4" hole.
  • Panel cleat attaches to strut nut using a 1/4" x1" machine screw
  • Click on following pictures for, larger, more detailed view

cross-section of strut

top view

three types of strut nuts

nuts attached to channel

panel tie-down cleat with strut

strut shown under mounted panel

strut at end of panel bank

mounted panel

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Page last updated:
May 28, 2014

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