Deck Reinforcement

[Miriam1]

Hi there,
My husband and I bought a house last year that had a hot tub lowered into the deck.  This hot tub has quit working so we decided to upgrade to a new model.  We've decided to put the new tub on the deck instead of sunk in, for two reasons.  One is that the previous owners didn't do a good job of having a level surface on the ground (used sidewalk blocks) which would be nearly impossible to fix so we became worried about our warranty.  The second reason is access to the panels if/when repairs are needed.

We have a deck contractor who will come on Saturday and install 4 screw piles to reinforce the area the hot tub will sit on.  He will then build beams across the screw piles and then deck boards on top of the beams. 

My question is:  does anyone know if this is enough reinforcement for a maximum weight 6000 pound hot tub?  Also, we are in Canada so we need to consider the weight of snow.....

Thanks!

[Kev B]

 The best way to know for sure, especially in your area is to pull permits and have the job inspected .
 Also, it should be your contractors job to know this....that is why he is the contractor.

[DaveMc]

I have been in construction for 45 years---what is a "screw pile"?

[summerside9000]

Screw pile would be perfect. The engineering needs to be done on the size of the pile and the soil conditions to determine its support capability.

If you provide the weight of the tub full of water and people the screw pile guy would be able to do the calc and determine what you need. If you live in Alberta its generally clay after a foot of topsoil.

There is usually a safety factor of 3 or 5 to 1 so as long as the beams he installed are up to the task that tub will be rock solid for years.

The pile goes beyond the frost line always anyways.

Google screw piles and see what comes up.

[DaveMc]

Of course a type of "Pile"--

[Tman122]

I have been in construction for 45 years---what is a "screw pile"?

It is made of metal and screws into the ground. Kinda like one of those dog leash hold downs you screw in by hand. Screw piles have different accessory's you install on top of them to hold post's, beams, ect. And you don't screw them in by hand. It uses a special machine attached to a bobcat/backhoe to screw them in. Depending on the soil that can work real well. Here in Minnesota they need to be 6 feet long or more to hold a calculable load because of our frost conditions. This can cause all kinds of problems with placement. They don't screw through big rocks no matter how much you screw them and you end up having them slip when you try and install them. This makes a hole that you might as well clean and fill with cement. But in the right soil conditions they are cheaper and less work than concrete footings.

[DaveMc]

Thanks--my knowledge file just had a boost!---here in California we put hot tubs on 4 to 6 inch pads or the equivalent but building we "drive Plies"---like 12" x 12" by 100 foot concrete piles in to the sand and dirt until we hit rock or the coefficient of friction is such that it is equivalent to hitting a rock bed---all our buildings (except the older ones) are on piles on one type or another.---I just hadn't heard the term "Screw Pile"---

[Tman122]

http://www.postech-foundations.com/images/164/Spa_vistech_postech_screw_pile_pieu.JPG.jpg