2
There are four basic styles of foundation for your tub. You
may consider a concrete pad, a gravel pad, piers made of
concrete or treated wood, or a deck.
3.1
A concrete pad forms an excellent base for your tub. A
properly poured 4” reinforced pad will be stable and
resistant to frost heave. Size the pad so that the sides are
about as long as the diameter of the tub. Example: For a
tub 6’ in diameter, pour a 6’ x 6’ pad.
3.2
A gravel pad can be a simple foundation for a tub in
some cases. If the ground on the site is compact and
stable soil, sand, gravel or rock; a layer of pea gravel (or
course sand) on top can be used to establish a level
foundation for your tub. However if the soil is unstable,
soft, duffy or muskeg, a gravel pad will settle unevenly
under the weight of the tub and is not a good choice. If
you choose a gravel pad, make it larger than the diameter
of the tub by about 3 feet. Example: For a 6’ tub, make
the pad 9’ in diameter. The thickness can vary depending
on how much gravel is needed to level the site. Typically,
2 to 4 inches is sufficient. Smooth with a rake and check
with a carpenter’s level.
3.3
Another alternative is to use
adjustable concrete pier
blocks
as a foundation. This type of pier block is available
at most home improvement stores and allows you to
adjust the level of the tub after it is in place. Piers can be
set into the ground to make a solid foundation for the tub.
This method involves building a small but strong wooden
frame or cribbing to support your tub.
Typically four piers should be used, and the wood timbers
should be 4” x 6” or bigger. The bottom of the piers must
rest on stable material.
3.4
Another option is to
install the tub on a deck
.
Installation on a wooden deck can be a good choice. Be
sure that your deck has been designed to support the
weight of a full tub (1500 - 8000 lbs depending on the size
of the tub). Have the deck inspected by a qualified
architect or building engineer prior to proceeding.
If surrounded by a deck, the deck can hide the heating
system plumbing. If on top of deck, the beauty of the tub
can be better appreciated.
NOTE:
During assembly, you will need about 3 feet of
space all around the tub for the tightening process. If
necessary, assemble the tub a few feet away from its final
position, then lift, slide or lower it into position (with help).
Section 4: Tub Supports – 4x4 Joists
Time needed: Approximately 20 minutes
Important! Choose a
dry day
to assemble your Tub.
The floor of your tub is supported by pressure-treated 4x4
joists (included.)
Prepare the joists by laying them out as shown.
The tub floor will sit directly on these. This allows air
space under the tub and allows the drain enough
clearance to pass under the staves. The weight of the
tub which is supported on the timbers. The staves do not
bear the weight of the tub! Once again:
DO NOT SUPPORT
THE WEIGHT OF THE TUB ON THE BOTTOM OF THE
STAVES.
The flat floor of the tub should be directly on the
joists.
Fig. 4.1
Use your level to get the joists level in all directions. Joists
must run perpendicular (at right angle to) the floor seam.
See Figure 4.1 for the proper position. Take care that
they do not interfere with the preferred position of the
floor drain. If necessary move the joists slightly. It is not
necessary to glue or nail the joists in place.
Fig. 4.2
Summary of Contents for Cedar Hot Tub
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