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Construction Details

Spa Enclosures

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Take the time to build a strong foundation and you'll enjoy your Summerwood spa enclosure for years to come.

In this section, you will find detailed information about enclosure foundations - from the various options available for stabilizing or leveling the base of your structure, to tips on how the components of your spa enclosure foundation should be laid out. How long it takes to create your building's foundation will depend on the size of your structure and the type of foundation you choose.

If the location of your new Summerwood enclosure is on soft, sloped, or uneven ground, do not worry. This section will show you how to build a solid foundation so that your spa enclosure is level and sturdy regardless of the type of ground it rests on.

There are a number of effective ways to create a level foundation for your spa enclosure. Most people build their enclosure on a concrete pad because the hot tub is very heavy and concrete is waterproof. If however, you'd like to use a different foundation option, we've made them available for your reference:

Patio Stones | Cinder Blocks | Super Spikes | Sonotube/Concrete Footings | Concrete Pad

Patio Stones

Level of Difficulty: Simple

Patio stones are the simplest method for supporting a wooden floor. They provide an effective foundation when the ground is relatively level (ie within 12" from side to side or front to back) and the structure is not too large. If your spa enclosure is larger then 150 sq. ft. you may want to consider one of the other foundation options. Patio stones are readily available at your local building supplier and are usually reasonably priced.

Please note that patio stones can be used on a spa enclosure provided that your floor joists are upgraded to at least a 2 x 8 support system. The hot tub is extremely heavy and you'll want to support it effectively. If you're going to be building your enclosure on a patio stone foundation, you may also want to consider covering your floor with tiles or linoleum (something water proof) so that your floor does not rot with the excess water that will be coming out of the tub.

A Word About Patio Stones

  • In order to use patio stones, your spa enclosure must have a floor (included with your enclosure kit package).
  • Patio stones are not shipped with your kit.


    Patio stones are shown under a wooden floor.

Patio Stones & Your Spa Enclosure

Here's what you need to know when laying the foundation for your Summerwood floor using patio stones

  • Lay out your patio stone foundation proportionately to the floor frame by placing your patio stones approximately 3-feet apart underneath the 2 x 6 pressure treated runners. Your floor frame will have the dimensions of your structure (e.g. 10ft x 12ft).

    ideal placement of patio stones underneath the floor runners.

    Notice how the patio stone does not extent past the floor's exterior.
  • Your patio stones should not extend past the perimeter of your floor (past your rim joists), as this will affect the installation of the skirting. Ensure that each patio stone is placed "squarely" underneath the runners.
  • The next step is to level your entire floor using shims. Any material that can be used to level your floor on patio stones are called shims. They can be made of wood or even metal. Cedar shims (cedar shingles) are a popular choice because they are durable, long lasting and resist decay. You will likely have some wood scraps lying around that can be used to shim your spa enclosure floor.


    Cedar shingles are used to shim the spa enclosure floor and make it level.

  • Your patio stones should not extend past the perimeter of your floor (past your rim joists), as this will affect the installation of the skirting. Ensure that each patio stone is placed "squarely" underneath the runners.


    Position your patio stones squarely underneath each runner for maximum floor support.

What We Recommend

When using patio stones to level your spa enclosure foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):

  • To guard against a sinking floor, use 2" x 12" x 24" (or 24" x 24") patio stones to distribute your cabana foundation evenly across a large surface area.


    a 2 x 12 x 24 patio stone is shown

  • Whether you use small or larger-sized patio stones, remember to space them apart accordingly. For example, if you use 12" x 12" patio stones, position them closer to each other. If you use 24" x 24" patio stones, you can place them further apart.
  • You may want to consider the option of adding an even layer of crushed stone underneath your patio stones. This can help with drainage and achieve a more level ground for your foundation.

Cinder Blocks

Level of Difficulty: Simple

Structurally a very strong foundation option, cinder blocks are another easy way to level your spa enclosure floor. They can be purchased from your local building supplier and may be used to level an enclosure on a moderately steep slope.

As with patio stones, cinder blocks can only be used in situations where a floor is part of your building. Please be sure to check with your local by law authorities and ensure that the foundation option you are selecting is good for your intended use.

Please note that cinder blocks can be used on a spa enclosure provided that your floor joists are upgraded to at least a 2 x 8 support system. The hot tub is extremely heavy and you'll want to support it effectively. If you're going to be building your enclosure on a cinder block foundation, you may also want to consider covering your floor with tiles or linoleum (something water proof) so that your floor does not rot with the excess water that will be coming out of the tub.

A Word About Cinder Blocks

  • Cinder blocks are not included in your kit.


    cinder blocks may be used if the ground slopes considerably

Cinder Blocks & Your Spa Enclosure

Here's what you need to know when laying the foundation for your Summerwood spa enclosure floor using cinder blocks:

  • Cinder blocks generally have dimensions of 8" x 16". While they provide uncompromising strength, their size and weight may cause your enclosure to sink if the ground below it is soft. Use multiples of cinder blocks and overlapping rows to guard against any sinking.


    typical cinder block

What We Recommend

When using cinder blocks for your spa enclosure foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):

Attach a skirt to your spa enlcosure to hide the cinder block foundation. We provide one row of skirting which you can use to cover the foundation underneath. Skirting can also help to keep pesky critters out from the bottom of your enclosure. If you'd like more rows of skirting (because your structure is elevated), they can be purchased when you place your order.

  • Attach a skirt to your spa enclosure to hide the cinder block foundation. We provide one row of skirting which you can use to cover the foundation underneath. Skirting can also help to keep pesky critters out from the bottom of your spa enclosure. If you'd like more rows of skirting (because your structure is elevated), they can be purchased when you place your order.

Sonotube/Concrete Footings

Level of Difficulty: More Challenging

Sonotube, also known as concrete footings, are used in situations where a spa enclosure needs to be raised, the ground is very uneven, or a building permit is required (i.e. in some areas a building permit is required if the area of the structure exceeds 110 square feet). Check your jurisdiction's building codes for rules and regulations.

Concrete footings can be expensive to install, as they must be used for your entire spa enclosure. However, they provide the necessary support for structures that are, for example, situated on a steep slope.

If you're considering the use of concrete footings for your spa enclosure, you'll have to take the floor with your building. Be sure to check with your by-law representatives to make sure that this type of foundation is a suitable option for your intended use.

Please note that concrete footings can be used on a spa enclosure as the foundation provided that your floor joists are upgraded to at least a 2 x 8 support system. The hot tub is extremely heavy and you'll want to support it effectively. If you're going to be building your enclosure on a concrete footing foundation, you may also want to consider covering your floor with tiles or linoleum (something water proof) so that your floor does not rot with the excess water that will be coming out of the tub.

A Word About Sonotube/Concrete Footings

  • Concrete footings are not included in your kit.
  • If you prefer some experienced help when pouring your concrete footings, simply tell us. We are happy to recommend contractors in your area.


    An example of what concrete footings look like installed on a slope.

Concrete Footings & Your Spa Enclosure

Here's what you need to know when laying the spa enclosure foundation for your Summerwood floor using concrete footings:

  • Before you begin digging holes for your concrete footings, it is very important to check with your local area's building codes for rules and regulations. You can also contract the services of an experienced building inspector to help you determine the appropriate size and depth of your concrete footings, before and after they have been installed.
  • Contact your local utility company to check if you will be digging near underground cables or gas lines.
  • Once you have confirmed the legal size and depth of your concrete footings, you can dig the holes by hand with a digger or ask a friend to help. Your local hardware store will be able to offer other digging suggestions that work optimally in your area.
  • When your holes are complete, you can either pour concrete directly into the holes and set your structural beams onto the concrete later, or intersperse tubes in the ground and pour concrete until it is level. Later, the tubes will be cut and your structure affixed to the tubes.
  • Concrete footings should generally be 10 inches in diameter and drilled well below the frost line. The positioning of your concrete footings should be similar to the layout for patio stones . We can provide that to you when you purchase a kit from us. Please note that this does not apply to plans purchases.
  • Let your concrete footings set thoroughly and properly.
  • If you'd like to lay a gravel base to ensure that water doesn't accumulate around your footing, 6" is the recommended amount.
  • To easily attach your spa enclosure to the concrete footings you've poured, consider sinking a bolt into the footing. It's not necessary to do this but it may make your installation easier.


    Depiction of a standard concrete footing with a gravel base and a j-bolt that can be used to affix a spa enclosure floor to the footing.

What We Recommend

When using sonotube/concrete footings for your spa enclosure foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):

  • When using sonotube/concrete footings for your spa enclosure foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):
  • In some situations, it may be necessary to use beams in lieu of runners to comply with regional building codes.
  • Set your footings 6" from the end of the beam and sides

Small Spa Enclosures - using runners

Use the supplied runners. Simply J bolt thru the runners and secured with a washer and nut are the easiest and simplest way to go. They should be placed every 4' in any direction.

Large Spa Enclosures - using beams

Use 6x6 post brackets in your concrete footings. There are several varieties, visit your local hardware store to find which one is common in your area.

The floor will rest on you 6x6 post piece. You will have to level your floor and the easiest way to do so is with these posts. Cutting the small post pieces to obtain level is far easier than trying to shave beams themselves.

Framing and Beams/Runners

Think of our floors in building depths. Our floor joists always run from the front of the building to the back.


Footings spacing from the front of the building to the back should be approx. 5' - 6' apart.

Building DepthLumber Dimension
4' - 8'2x4
8' - 13'2x6
14' +2x8

Beams and Runners will run the length of your building. From sidewall to sidewall. They run the opposite direction of your floor joist.


Unless otherwise upgraded, our floor members come in the following dimensions

Use the following chart to space the footings from side to side.

Spacing of concrete footings
2 x 4 floor joists 2 x 6 floor joists 2 x 8 floor joists
Building length (2 - 2 X 6 Ply Beam) (2 - 2 X 8 Ply Beam) (3 - 2 X 8 Ply Beam)
8' 68" 68" 68"
10' 42" 42" 92"
12' 54" 54" 116"
14' 41 3/8" 66" 66"
16' 49 3/8" 78" 78"

You can also look at our beam layout PDF for more help.

Concrete Pads

Level of Difficulty: Elaborate

Concrete pads provide a concrete base onto which your spa enclosure walls can be mounted. This foundation option is generally used if you are:

  • Installing a hot tub that cannot be supported by a wooden floor.
  • Housing pool equipment (ie heater, filter, pump).
  • Installing a plumbing system.
  • If your local by laws require you to pour a concrete pad for your spa enclosure
  • Making your structure permanent

A Word About Concrete Pads

  • Concrete pads are an expensive foundation option and we recommend that you enlist the services of an experienced contractor who is aware of local regulations and will ensure that your structure complies with regional building codes.
  • Pouring a concrete pad means you have the option of not having a floor. In this case, the walls would be mounted directly into the concrete using a pressure treated bottom plate and a gasket seal to prevent moisture buildup.
  • Your hot tub would be placed directly on the concrete pad and you wouldn't have to worry about how heavy it is and whether the foundation can support it.
  • If you are replacing an existing enclosure with a larger size it is possible to frame on to the existing concrete pad. Using pressure treated materials you can extend the pad so that the size matches that of your new structure.


    An example of a Spa Enclosure on concrete pad

Concrete Pads & Your Spa Enclosure

Here's what you need to know when laying the foundation for your Summerwood spa enclosure using a concrete pad:

  • Before you begin pouring your concrete pad, it is very important to check with your local area's building codes for rules and regulations. Frost lines and seismic considerations will all dictate the type of pad and enclosure foundation you can build.
  • If you enlist the services of an experienced contractor, they will likely select the appropriate type and amount of concrete mix for you. Choosing the right mix depends on the climate in your area (i.e. warm or cold) and the type of spa enclosure you will be erecting on the concrete pad. If you've elected to mix your own concrete, contact your local building supplier for assistance. They will also be able to help you determine what tools you will need.
  • Once you have chosen the site for your concrete pad, you will need to dig a trench. We recommend a 3-foot wide trench, but size will vary depending on your location. Grade or level the center of your trench.


    Dig a trench to start building your concrete pad.

  • Fill the bottom of your trench with crushed stone to maintain proper drainage.
  • Construct a concrete footing form using stakes and 2" x 8" lumber to mark the corners of your pad. It will be like building a sandbox or mold for your concrete mixture later. Ensure that your corners and the box are square.


    a concrete form will keep your concrete in place

  • It is very important to pour a concrete pad that is the same size as your spa enclosure. Do not pour your pad according to your structure's exterior dimensions, which tend to be bigger than the actual building (siding allowances are not included in the measurement because they are positioned over the concrete pad).

    If you pour a concrete pad that is bigger than your building measurements, you will increase the likelihood of water leaking into your building (creating a proper seal between your wall and your concrete pad is difficult).

  • Pour your ready-mixed concrete into the mold you've created. Agitate the concrete to work out air bubbles. Level the concrete and use a piece of lumber (e.g. 2 x 4) to screed (i.e. smooth out) the surface of the pad. Apply more concrete to the sunken areas to bring the entire pad up to the same level.
  • Next, use a float to further smooth out the surface of your concrete pad. This will be like applying icing on a cake but without all the fun decorative whorls. Keep going over the concrete until you have worked out any moisture or remaining air bubbles. Avoid marring the surface of your pad.


    An example of a smooth concrete pad

  • When your concrete pad begins to set, run an edging tool along the inside of the mold. This will be like removing a cake from its baking tin. This technique will help make it easier to remove the forming boards later.
  • Properly finish and seal your concrete pad using one of the following methods so that your floor lasts for as long as you have your spa enclosure. Try:

    - Properly finish and seal your concrete pad using one of the following methods so that your floor lasts for as long as you have your spa enclosure. Try:
    - Cover your pad and allow the concrete to set evenly for approximately 48 hours.
    - Apply a protective concrete sealer.

  • There are several ways you can affix your walls to your finished concrete pad: use a J-bolt (available through any building supplier) or a concrete screw (Tapcons). Using a heavy drill, screw your J-bolt or Tapcon through the bottom plate and into the pad. We recommend that you use 4-inch screws and place them approximately every 12 to 16 inches apart.


    A picture of a tapcon

  • Our siding is designed to overhang the bottom plate of the walls by approximately 1 inch. Should your concrete pad be slightly larger then the structure, simply saw off the overhang so that the bottom of the plate and the siding are flush with each other.


    Make sure your bottom plate and siding are flush

What We Recommend

When using a concrete pad as your spa enclosure foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):

  • When using a concrete pad as your spa enclosure foundation, we suggest the following (depending on the size of your structure, the recommendations below may be adjusted accordingly):
  • Consider installing gutters to help redirect water away from your foundation and walls. This is always a useful addition, especially if your concrete pad is larger than your spa enclosure.
  • If you are installing conduits for electrical service or plumbing, you must do so at least 4 1/2 inches from the edge of the pad so that the walls will have room to sit.
  • Pouring a partial concrete pad tends to create problems in the future (with warping and the 2 foundations in use might sink or move at different times and degrees). We recommend that you pour an entirely new pad if necessary. Extending existing pads is possible but not advisable.

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