Hot tubs are heavy. You cannot put them anywhere you want. You certainly shouldn't sing, "He ain't heavy, he's my hot tub..."
Clients often ask me how heavy a hot tub is.
A four person hot tub holds 300 gallons, or so.
A six person hot tub holds 500 gallons, or so.
And an eight person hot tub holds 700-800 gallons of water, or so!
A gallon of water weighs 8.35 pounds, if I remember my 9th grade lab science class.
So, looking at this picture, this is a six person hot tub and holds 500 gallons.
That's 4175 pounds of JUST WATER!
This hot tub has a wood exterior, fiberglass interior. It weighs almost 1000 pounds.
If you fill it with six people, averaging 175 pounds (conservative estimate), that's an additional 1050.
Theoretically, full of people and water, this little fellow weighs well over 6000 pounds.
A 6000-pound anything needs a really sound, strong foundation.
Your basic, average, even professionally-built deck, is not made to hold 6000 pounds in an area of about 50 square feet. And certainly it cannot hold that weight continually for a long period of time.
This deck was founded very well. It is supported by double, built-up beams, resting properly on 6x6" pillars, with 2x12" joists, spaced 16" apart with blocking between each joist to prevent racking!
THIS IS A WELL-BUILT DECK! BUT DO YOU SEE THE SAGGING BEAM?
I took the picture above by resting the camera on a level step away from the hot tub. It might be a bit hard to see, but that deck is leaning downward, to the left.
Can you see how far it has sunk below the bay window on the left? About 4"! And that sinking is happening just around where the tub is located.
THE TUB IS SINKING. IT HAS BEEN THERE FOR 3 YEARS.
Another couple of years might have been catastrophic!
So why is it happening?
The column in the immediate vicinity of the hot tub, and beside that bay window, is obviously sinking.
An engineer friend of my says that once something starts sinking, it will usually continue.
Given the professional nature of the deck, I am going to assume it was installed properly.
That means it is 24" deep, with a 12" concrete footer onto which a base is attached and the column is secured.
EVEN IF THIS SINKING COLUMN IS FOUNDED PROPERLY, IT IS NOT INTENDED TO HOLD 6000+ POUNDS INDEFINITELY.
And so it is sinking.
And it's too bad, because this is a wonderful deck and the repair will require a complete rebuild of that beam and column, even after the hot tub is removed.
My recommendation: before you do something like add a hot tub to a deck, get some professional help to determine what it would need to make it safe and secure in the long run. After all, gravity works! Every time.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560
Interesting but is it fixable? In other words what is the water table in that area? What would you recommend and how would you proceed if it was your home?
Good Morning, Jay. Didja every have those days where you keep getting that sinking feeling...
Yes, water if very heavy and people forget that. Yes, I could see that being a costly repair.
James - the water table varies from area to area here. And I have no idea what it is now, although we have had our share of rain lately! If it was my deck, the hot tub gets removed, to never be added there again. That's what the ground is for! And that column needs to be removed and refounded. The deck can be saved.
Every day Michael, every day I walk into a flipper!
Debbie - things were done very well, if it was just to be a deck, even with the occassional party out there. But not for this kind of weight. Wait til you see the gazebo tomorrow!
Interesting post - imagine how bad it would have been if the deck was not constructed properly. Don't think it is a good idea to have a hot tub on a deck anyway - this just cements it.
Jay - many people have no real idea how much a hot tub weighs (I know I didn't until I read this) and they purchase the hot tub, probably getting the appropriate info from the sales person on where it should go/should not go, but I guarantee, they all go home, and think "It will look perfect there!" with no regard to the weight/support factor.
Good morning Jay,
Great blog, great information...important weight factor to consider, that is usually overlooked. Thanks for sharing!
I guess people don't think about little things like weight...and when you add a couple of people a lot of potential for injury.
K.C. - the best deck hot tubs are the ones cut into the deck with their own foundation. That way you step down into it, and the deck isn't influenced.
Carol - it's just simple math. I looked up how many gallons the things hold and went from there!
Lisa - you are right, it is overlooked. I see sinking decks all the time!
Gary - how fun would it be to have a relaxing soak in the hot tub and end up below the deck!
Gotta love it...people never water as being heavy....it caves in foundations, decks, roofs....lots of fun when it's ice or snow...water can be a weighty subject !
'Twas the weighty subject today S&D! Water and gravity always team up! Kind of like you two - one plus one equals three.
TRUE TRUE TRUE! I have been in the basement of a home with an indoor hottub once and the supports below the tub made it good for nothing more than some storage. The rest of the basement was finished.
Wow, Joe. That must have added a LOT of humidity to that house! Not always good...
Jay, Just one more reason when we got our hot tub we had a separate, lower section of deck built to support it. At least if we have a problem some day it'll be contained to just that portion of the deck.
That is the way to go Bliz. Certainly it will need additional support - it is a long-term dead load, with a sometimes live load added to it.
Jay fantastic point as i see so many hot tubs placed on older decks that is a recipe for disaster. If you want to know how much a hot tub weighs, try and move one... it is not pleasurable
Scott - it really is a simple calculation to figure out how much your hot tub might weigh. And don't be conservative when you figure it out, like I was in the post.
Certainly, being circumspect, people should find out if their deck can actually hold the thing! The odds are almost certain the deck cannot.
Jay, floor loading is an important issue in commercial real estate. In this case, I can see where it applies to residential real estate.
It does Michael. Even in bedrooms, where people have created offices with very heavy filing cabinets or book shelves. The floors aren't meant for such a heavy load in such a small square foot space.
Great Post! I saw a similar set up several months ago on a home my husband and I was looking at. The hot tup was much too heavy for the deck but the agent kept telling up that it was normal.....NOT.
I've learned so much from your post here on active rain. I sorta feel sorry for the seller and agent because you have provided me with a lot of insight on possible problems and things to watch for.
Big Thank You!
Jay, wow, thanks for another stellar lesson! So now I will look even smarter when we see that hot tub on the deck....
You are very welcome Carolyn! For an agent to say something like that is "normal" indicates inexperience and inconsideration. Not to mention ignorance!
Andrea - instruction, instruction, instruction. This is something I see a lot, but the evidence as to what is causing it was very visible.
Wow. This can really do some damage that would be very costly to repair. People dont seem to like hot tubs in my area anyway.
This is a great title and a great tip. Get a professional opinion before installing something or doing a project around your home. When Home Inspection Day Arrives, it will be much better to have been extra cautious on the safe side than extra "repair bill" sorry. I have also heard negative showing comments about "Harry Homeowner" basements. Do your extra homework to avoid the extra repair bills prior to selling your home.
Just reblogged with above!
Chuck - in this case, they no thinko in advance-o. That's perfect Spanish, by the way. I probably have hot tubs in one out of fifty houses.
Cheryl - thanks for all! In this case, I don't think things were extra cautious, but the deck construction did not anticipate a hot tub. Nor should it have!
We finally settled on a cement pad. Thank goodness.
Good idea Suzanne! The ground can hold a lot of weight!
Your title roped me in . This is good iinformation. I guess in the old days the same could be said for people who had water beds , which was fashionable when I was younger , and dinasours ruled the earth
Great post Jay...Well you don't see them much these days, but gets you wondering what the implications are for people with water beds.
Charlie - water beds aren't really that heavy per square foot. Well, that might depend on the two people who fill it up though! The deck is not as sound structurally as the bedroom, generally.
Howard and Susan - see my answer above! Two water bed comments back to back! We had a water bed for a long time, and I never slept better!
In my experience, hot tubs are used even ess than swimming pools and are extremely expensive to keep in service and maintain.
Very timely post --- thank you. My wife and I are researching a landscaping/deck/hot tub project for our backyard and I'll be sure to keep these things in mind. I had not thought about the weight implications of a tub on the deck itself because our plan was to rest the tub portion on a slab or crushed gravel. But still, this is great to know.
JAy,
I think most people never put the numbers to the test. That is 3 tons of fun going on there ; )
Jay, Great post
Unfortunately we cannot take into count mother nature, above ground or under.
Your post made me think of water towers you see here and there and the size of the footing that they must require.
Enjoy the day
Not around here Bob, but they sure are expensive to keep at a constant temperature!
Rob - that kind of a foundation is perfect. You could build the deck around the tub and step down into it!
It is Don. Few people bother to calculate the weight. It took me less than a minute this morning. I needed to know how many gallons a 6 person tub holds!
The foundations on those are really deep Don. Those structures are heavy!
Jay, what a great information blog for those hot tub lovers. Here in Manhattan New York we usually do not have any hot tubs in individual condo units. However, some of the penthouses or top floor apartments sometimes do have hot tub if they have outdoor space (terrace). Now next time I see them, I will be wonder about if the foundation that hot tub sits on is strong enough.
I will bet you're safe there Eileen. They probably built that support into the original structure, knowing it would be there.
You know when you apply math to anything, it gives it a different perspective...Engineers have to acknowledged for their work because without it, things just wouldn't function or be available as much as they are...This is a good awareness post Jay thank you
I never looked at it like that but knew it was very heavy and the support needed to be extremely sturdy. I remember the 8lbs gig for a gallon from school too (lol).
Thanks for doing the math and pointing out how serious this is
Jay - Few people consider the weight issue when adding a hot tub. A home I remodeled several years had a 6 person hot tub on the rear deck that needed to be replaced and because of weight and access problems, the job required a crane.
Wow, you know, I never thought about the effects of all that weight. I always learn something from reading your blog, Jay. In fact, I caught a serious issue during one of our walkthroughs recently because of reading your posts! Thanks for all the information!
Hi Jay, Pretty amazing pics. I've also seen some basement walls caving in because there was no rain spout along the side of the building. Scary !!!
Timely post Jay. My most recent buyers thought a hot tub was a negative in the home. I remember a time when hot tubs were all the rage. Now they seem to be a selling negative.
Richie - thems heavy stuff! But you already knew that. You're right, not everyone does the math.
David - I had to look up how many gallons a 6 seater holds, and from there it was easy.
John - I bet you needed a crane! You wonder how they did it in the first place!
Thanks Amanda. We try to be instructive!
Thanks Bill. Water is the issue, no matter where it is or how it is contained!
Carla - they may be, but wait a minute and they will be back along with zoot suits.
Jay, I should have known this, but had never thought of it before... Thank You, my future buyer clients thank you also ;-)
De nada Chris! Just trying to be instructive and helpful! As usual...
Ouch, that one is going to be expensive. I was unaware of the full weight of the water in the hotub. That's crazy!
That ain't the only thing Justin! Wait til you see the gazebo!
Jay -- Going back to waterbeds - we had a sales person tell us that the 200 gallon waterbed bladder would be just fine with a single 2x perimeter base under the pedestal. My math told me that with a couple of people - we would be pushing a ton - and I went with spreading that weight over a larger area.
Steven - we had a queen waterbed for a long time and it was only 50 gallons! That mattress must have been really thick! Smart, though, to spread it around a larger area.
Jay, this blog title made me laugh. Thanks. I think a lot of people do things without really thinking them through. Hot tubs on decks, removing walls, etc. People need to hire experts to make sure it's a good idea.
Eric - there's a parable about that. Let him who has ears to hear, hear!
Jay - I'm sure they are not the first person nor the last to have a problem like this.
Just by your initial mathmatical equation it would almost be like driving my Armada onto a man made deck. No thank you. I would hate to get outta that mess. Seems it would make more sense to "bury" it into the deck with the hottub on a concrete slab below the deck. It would look nice too and seem easier to maintain exterior condition. Great Post.
Jay:
Just goes to show that even a very well built deck is not enough for a hot tub. A structural fix is needed.
Jay, I love finding those things about 10 feet off the ground---any deck with a hot tub needs serious engineering.
Christine - for sure! I see this all the time, and will probably again very soon!
Gayle - this weight would be more concentrated than a car would! But its weight would be concentrated on four spots, and depending on where those spots are would determine how much sinking would be involved.
I agree Evelyn. These tubs should have their own foundations. The best ones I see are actually cut into the deck, and you step down into them.
Picasso Shadow - those are the best! Don't you just want to go out there with everybody in attendance at the inspection and jump around the tub!?
Very timely post for me since my buyer has focused on a home with a large hot tub on the deck!
Jay - that's a great breakdown on the weight of a hot tub. I installed a six-person hot tub at my house this year (on a concrete pad, of course), and I couldn't believe how heavy the hot tub was.
How the heck do people get those things on second story decks?
Good morning Jay. Not a big fan of hot tubs on wooden decks. Eventually most of them will give in and do the sag. I like a good thick concrete base when it comes to that kind of weight.
We have a ton of properties built on unlevel lots with decks off the back. I will keep an eye out for this while showing property. I know I have seen a few spas on decks before. Now that you explain it, it seems like a horrible idea.
Jay: Yikes! And yet we see so many hot tubs resting on decks every time we show houses. Thanks for the tips. Carrie
Dear Jay,
Yesterday, I showed a home that had this scenario enclosed in a building extension, without bothering to change the deck to a floor. There were more curious changes to the house that screamed "no building permit," so we moved on. I am always amazed at how much money people spend without thinking first.
Jay, I had no idea. Well, I know now!! Thank you for this instructional blog of information I needed a year ago. Yes, I've bookmarked for future reference.
Interesting and informative post. Thank you for the lesson.
Hi Jay, it's no waterbed, but i'm working with a tenant with a 2500 pound safe they want to put in their lease space. It measures 3'x4, so the load is distributed over 12 square feet. The question for the architect and engineer is whether this particular building will support that floor load...still waiting on the answer!
Haven't had this issue but this is a perfect reason why I follow AR.
Ginny - well, best to have a professional check it carefully!
Reuben - I guess with a crane, as John suggests above, or maybe they assemble it out there.
You didn't just put four bricks under it?
Randy - the soil, and a concrete pad, are made for that sort of thing!
Patrick - if the structure can't hold it, it's a bad idea!
Carrie - well, have a very, very close look, and include a professional if there is any question!
Dorte - probably best to move on. There's no point in having questions having overhead.
Beverly - glad to be of service! Maybe you can use it again.
Kimo - you are welcome. We try, we try.
I don't know what kind of structure you are talking about Tim, but if it is a wood structure I'm a'betting no!
Bill - and now that you know you might just run into it!
Sylvie - that's the best was to found them, but they need to be level too.
I would imagine that most people don't think through things like the weight of a heavy object. Hot tubs cannot just be stuck anywhere and everything be ok.
Thanks for all that information greatly appreciated..
You should write a Dr Seuss style book, "Oh, the inspections I have seen, wires here and wires there, pipes that go just everywhere!" and other assorted tales!
Rodney - you cannot stick them anywhere! And I see it all the time where people do!
George - glad you appreciated it and hope you can use the info!
Steven - In houses I look up and down, the things I find can make you frown.
I can inspect while I cook, I bet that I could write a book.
I put one blog to music: http://activerain.com/blogsview/2439712/seven-ways-to-kill-your-dryer
As a person who has several fish tanks, I do know the weight of water! My 225 Gal tank is on a concrete slab. Ever see structure damage from tanks?
Yes, Derrick Team, I have. Once a very large salt-water tank, I don't know how many gallons, was inside a wall, with an access behind you could walk into. They did not frame it well and it was pulling down the wall around and above it!
Always have it don and over done by a professioanl that guarantees their work. Time for some serious re-enginerring.
Jay, Good lesson on hot tub weights. I think they all need a diet!
Ric - the deck was, and is fine, with the repair of that beam and column. That weight isn't fine and needs to be removed!
Bob - they are fun I guess, but not on the deck!
I am not sure I would have wanted to go under for the pictures. Scary!
I figured if I could walk over without consequence, Marshall, I could go under if nobody was up there!
Great advice. Anyone who wants to put a hot tub on a deck really needs to make sure that there is additional framing and footing piers to support that extra substantial weight.
another thing I have not considered before....keep the good posts rolling!
I want to go down with the hot tub and a margaritta. Good point. Build it on a slab or make the deck reinforced.
For sure Jim. Most people don't go to those lengths unfortunately.
Jason - you're welcome! I intend to!
Gene - it's best to go down with it, and it makes for a more interesting new story later. How fun is it if the deck collapses and nobody was home?
Jay, that's great information you are sharing with us I never liked the look of those hot tubs sitting on a deck anyway!
My house has a old (read termite eaten) wooden deck area that used to house a hot tub & my husband wants to put a new one there. I told him I prefer to have the tub sit on the ground & built a new deck or patio around it... looks better in my opinion. Now your post is giving more amunittion to my argument... thank you!
That's more weight than a car with passengers. Good deck or it was.
Of course Monique - tell him it's a no brainer!
Jim - duh... I don't know what people are thinking sometimes. If there is thinking at all...
Great reminder. As a very qualified and accomplished DIY'er I have observed many decks (even without hot tubs on them) whch were significantly "underbuilt". Decks are a very common project taken on by DIY'ers that are seemingly easy to build but with little attention to proper structural foundation and bones. Most commonly I see that the attachment to the main structure is improper and footers not being proper. It is a commonly overlooked area in inspections, especially if there is not easy access to the underside.
Not commonly overlooked here Bill! I have problems on decks more than any other feature of a house! In Northern Virginia attachment to the house rules have changed dramatically over the years. You are right, it is a huge problem.
I was in the middle of an inspection yesterday, and the owners had a radio playing the entire time, on a station I wouldn't normally listen to.
On came a song I had never heard before, and suddenly your post title made a little more sense :)
You didn't know what it meant Reubs!?? Wow, so they had an OLD GUY station on?
Who's the artist?
Ha! Gotcha! The original singers could have decked a hall with their boughs. The other two who recorded it were mere pretenders.
I don't think so... The Hollies! :-)
Right, but you didn't know it until you Googled it...
How dare you...
they announced the artist's name on the radio :)
You still Googled it, admit it. Triple dog dare you...
You had never heard of the Hollies!
I am about to get a hot tub - (perk of being a Realtor - a client is moving and giving me a super nice one that buyer didnt want) - thinking about getting an EZPAD to put on grass/yard because I dont want on my patio - any thoughts/tips/advice on this?
You found an oldie but a goodie Nicky! Honestly I have never heard about an EZPAD! You have to make sure the foundation of the earth under the pad is secure however. Don't assume the ground will not sink!
Good morning Jay. This is sooooo good. Doesn't take an engineer to figure this out but it does require one to design the deck to support the weight.
Thanks Sheila. If you are going to add so much weight to a deck it has to be compensated for!