Now it is simply a matter of finding the area for each rectangle. It will simply ensure that the deck does not sink into the ground. Decks built ground level up to 2 feet off the ground can support up to 100 lbs per square foot; sufficient for most hot tubs. Thanks guys... my ladies really want to start hot tubbin' nightly and I want to indulge them, and myself. To safely install a roof deck, the roof needs to be able to support about 55 pounds of weight per square foot in general. While accounting for snow load in the U.P. Multiply each area by 50, and you have the number of pounds per square foot that each footing can hold. It’s possible that it could hold much more weight than 50 lbs. This includes furniture, people, etc. It also risks collapsing a deck. Just as 50 pounds per square foot is the minimum weight capacity for a deck built to code, so too is soil bearing capacity. The thickness of concrete is an important factor in load-bearing strength, but to conserve resources and avoid over-building, other factors are also taken into consideration. For example, a 2x4 lumber may hold a 4-cylinder engine comfortably but may not hold a bigger one. Calculating a tributary load is fairly simple if you have a standard rectangular deck attached to your house. Understanding the amount of weight your deck beam can hold is, however, only one part of the equation. Luckily, we now know how to calculate those loads since we did it a few paragraphs above. Dividing by 5 will allow you to determine that 4500 lbs is the max live load your deck can hold. Weight. That doesnât mean that your deck will suddenly have the same bearing capacity – it only means that your deck will not sink – ever. If your footing is 24â sonotube, then it is more than strong enough to support your deck. The spa filled has 320 gallons or 2672 lbs. That being said, most weight-bearing calculators for decks assume a default of 1500 pounds per square foot for soils. The next portion is to figure out how much weight this footing is going to hold. Below Iâve listed a few of the major areas that give a deck the ability to sustain large amounts of weight. If your deck is built on bedrock, gravel, or even sand, then youâll have a higher – and potentially even a much higher – soil bearing capacity. However, youâll have to get underneath — or at least have a good view of the underside of your deck – to see the dimension of lumber it was built with as well as to measure the distance between footings, footing type, and the type of hardware used. Again, knowing your deck lumber species can allow you to see if your deck is overbuilt. Figuring Out How Much Your Deck Handle As a general rule of thumb, if you have a deck that’s raised only a couple feet or less, it can support about 100 pounds per square foot. This calculator determines the size of each tributary area of your deck. But keep in mind those are just estimates. Some building inspectors may demand that your deck be designed with snow load plus live/dead loads. If you look at the joist span tables above, it doesnât take long to see that SYP is stronger than the other lumber species. Why? However, you can determine if your deck is overbuilt, which can give you an idea of how much more weight your deck can hold. A key indication of your fastener load bearing capacity is what youâve used to affix beams to joists and posts to beams. If you don't already have plans for the deck, draw up a sketch showing the size and spacing of bearers and joists (including the material if you can), the dimensions and materials of the decking itself and the details of how it is held up. Next, you measure the distance between the footings. Also, deck maitnance is key (waterproofing and that kind of stuff) to prevent the wood from rotting. Since a hot tub will more than likely fall into the area of just one, or maybe two, footings, we need to know that one footing can handle the weight of a hot tub. However, if you are using post to beam connectors, joist hangers, and hurricane ties to support your structure, then standard 10d nails are just fine – the hardware itself will provide most of the support. I spent a week at a vacation house on the Russian River, and the rickety deck (about 15 feet off the ground) had a pretty large 4-person hot tub jacuzzi on it. per square foot. for 7 occupants = 5655 lbs. Default is 50 psf which you can change. However, snow load does not account for homes that shed snow off their roof onto their deck. Have a look underneath your deck. 855 lb. That means half of the deck closest to the house is entirely supported by the ledger board. We get just over 19â for our footing diameter. The total load for each tributary area is then divided by the area of each footing in order to determine the load psf imposed on the soil. If that is the case, you could have the strongest deck frame in the world, but bad soil will cause your deck to sink under loads that the frame of your deck is designed to support. I highly suggest hiring a professional to check it out. per square foot. The average homeowner does not have the tools available to determine how much more weight your deck can hold than the … Generally, we’re talking about 50 pounds per square foot. 288/3.14 = ~96. Call your city's inspections department. Don't get confused with what weight you might think or want to load the deck with. So I think I'm going to get a pro out there to spec it out. Make the investment now to ensure you have a sturdy deck lest you get screwed later on. To determine the maximum load capacity of your deck, start by calculating its total area and multiply by 50 psf. Can you put a hot tub on a deck? Such calculations would hold if, for instance, the load is square. Add to this the weight of the tub itself and any filters, pumps etc and you will have a total weight for the whole thing. I have a deck. One square foot has 144 square inches – so for us itâs 288 square inches. The … Ask MetaFilter is a question and answer site that covers nearly any question on earth, where members help each other solve problems. For instance, a deck built on bedrock will have a bearing capacity of nearly 12,000 pounds per square foot. To calculate the load, you should use 40lbs per square foot for live loads (these are variable loads that are dynamic such as the weight of people and furniture) and 15 lbs per square foot for dead loads (this is the weight of the materials used for the construction of the deck) for a … Ask MetaFilter is where thousands of life's little questions are answered. Knowing your soil type is just as important. Then find the square root, and multiply times 2. Draw a rectangle from that point up to the first line halfway between the house and beam. If you drove a dump truck over it, yes this would throw all our calculations out the window. I went through the permits, but was not able to find a weight rating in there. There is no specific amount of weight that each weight plate can support, however they can only hold up to 10. It is always wise to contact a professional to get an accurate estimate of what your deck can safely handle. All of them did, I'm sure, have a solid foundation. The other half is supported by the footings supporting the beam. construction, and less joist overhang. A deck is built to hold 40 pounds per square foot as "live load", which is everything you place on the deck that can be removed. That means that the overall structure can support a load of people, or âstuffâ, of at least 40 pounds per square foot on top of your deck. Advice for building a back yard cabin,... Atlanta MeFites: Contractor recommendations required! On the other end, a 2x6 can support a V8 engine of between 600 – 700 lbs. Join 6,470 readers in helping fund MetaFilter. Soil matters. Calculating tributary loads is not difficult, as long as you have a diagram of your deckâs framing structure. At the beginning of the article, we determined that the total live load the deck could sustain was 4500 pounds, after subtracting for the âdeadâ load, which is the deck structure itself. is probably wise, youâll notice that North Carolina, for instance, only has an average snow load of 15 pounds per square foot. One of our last variables in determining deck weight bearing capacity, fasteners, are arguably the most important aspect of deck construction and the most overlooked. To calculate the weight of the deck, I’ll use a 10×10 deck for this example. Let's add the dead load of 10 psf to our number and we get 111 psf in the area under the tub. The key is to make sure you use the appropriate nails or structural screws, as indicated by that piece of hardware. If only nails were used, without hardware of any type, then you might want to think twice before placing an 8000-pound hot tub on your deck. Letâs take a 12×10 foot deck as an example. The gross vehicle weight (GVW) is how much the trailer and its payload weighs together. Reverse that and divide your area by pi. tub + 3500 lbs. and eek out a longer span. Once you know how much the soil beneath a deck can hold, next you can figure out the weight of the deck. This means that if you had a 100 square foot deck (10′ x 10′), you’d be able to hold 5,000 pounds above it (assuming the weight was evenly distributed). Then check out this footing load table, which can tell you exactly how big your footings need to be based on the size of the post, the span of the beam, and the length of your joists. He is passionately interested in home improvement, renovation and woodworking. 3000/1500 is 2. Absolutely, but weâve got to know how much weight each of our footings can handle. How much weight/ How many people can my rooftop deck hold? Remember that pi x diameter equals a circleâs area. As always, thanks for taking the time to read this article. For instance, a 3-ply 2×12 beam can span 8â between footings when joists are 12â long when both SPF or Western Cedar is used. Simply because it is assumed that you will clear your deck prior to inviting 20 of your friends over for a beer on that deck. This is for soils that are a mix of loam, silt, and clay, which also happens to be one of the weaker types of soil. Once we find out the appropriate diameter, we can then know if our deck is overbuilt and, thus, capable of sustaining more weight. One of the best tools in your arsenal to determine deck weight capacity are deck load calculators and max span calculators, widely available online. A well-made maple skateboard deck may hold around 220 lbs, but it is still likely to snap if you land incorrectly. If you find that your deck joists are 2×10, but the deck load calculator only mandates 2×8 joists, then you can safely assume your deck is much stronger than 50 pounds per square foot. You cut a big hole in your deck, then pour a concrete foundation on the ground to support the weight of the hot tub, and drop it in. Letâs take our 12×10 example and investigate the weight capacities of different types of beams. Therefore, a deck of 120 square feet multiplied by 50 shows that your deck can hold 6000 pounds, including the structure. Using the example above, if you have a beam of that size built with SYP lumber, and you have a span of 10â but with three footings instead of two, you can safely assume the overall weight-bearing capacity of the deck is far more than 50 pounds per square foot. How does this affect load-bearing capacity? Do I need to hire a professional to do that? If you want to host a large party on your deck but still arenât sure if it can handle the weight, itâs best to contact a building engineer. Please feel free to drop me a line and let me know how I can improve this article for future readers. Today we give you the short (for us) answer to this question, How much weight can a floating shelf hold? SYP lumber can span 10â – 2â more than the other species. Since we are shelf geeks and own a company that manufactures floating shelves, this is an easy one for us. Log in to Reply. Add that to the typical 50 a deck is built for, and youâve got a deck that needs to hold 120 pounds per square foot. If structural screws were used in conjunction with deck fastening hardware, then itâs likely your deck weight bearing capacity is more than the minimum. And it does not really matter because the frame of a Trex deck is what supports the deck, not the deck boards; therefore, a Trex deck is no stronger than a lumber deck. Lastly, weâll take a look at the different types of lumber you can use for your deck and how it will affect the weight capacity of the overall structure. Is there a way for me to test how much weight it can hold? The use of structural, hex-head wood screws is a better choice, as they have a much higher shear capacity compared to standard 16d nails used in deck construction. Above, we calculated the tributary load of a deck, which tells us how much weight each footing can sustain. It is only slightly stronger than SPF lumber or Redwood and Wesetern Cedar. They will tell you exactly what the code is for that sort of thing. If not, youâll have to get dirty and go underneath your deck to take some measurements. Now you have an area for each footing. Eugene has been a DIY enthusiast for most of his life and loves being creative while inspiring creativity in others. In that case, youâll need to know what the average snow load is per your geographic region – a snow load chart helps. That is a big range. If your deck is built to code, then it is designed to hold a minimum of 50 pounds per square foot, of which â
of that total is the âliveâ load. That number is simply a minimum requirement. I've never in my life seen a sunken hot tub, though I know they exist. The answer is, a lot of weight—if it is done right. Help me make my curtains as noiseproof as possible. If you don't already have plans for the deck, draw up a sketch showing the size and spacing of bearers and joists (including the material if you can), the dimensions and materials of the decking itself and the details of how it is held up. The GVW includes the weight of the trailer itself, plus its payload and anything that adds to the total weight. Knowing the tributary load of each footing can help us determine the diameter of each footing. How much weight will a .125 inch wood screw support? It means different types of soil vary in terms of how much weight they can support before whatever they are supporting sinks into the earth. Also, some of the most highly durable skateboard trucks have weight limits of 250 lbs. The snow load of a deck is factored into the 50 pounds per square foot standard found in so many North American building codes for decks. So, if the spa is less than 100 pounds per square foot you likely have nothing to worry about. An engineer or your local authority should be able to give you some idea as to whether it is capable of holding the weight in addition to the weight of the number of people that could fit onto the deck. Wondering how much weight can a tension rod hold? On the other hand, if you build in a ground-snow load that exceeds 40 psf, then you can enter your snow load in the “Live Load” field to size a joist span to handle heavy snow. What started as a small gathering ended up pretty large, and there were a lot of people on my deck. or 7 lb. Youâll measure the distance from the ledger board to the center of the support beam and draw a line. Remember, you donât need to be a structural engineer to determine how much weight your deck can handle. The American Wood Council states that cantilevers are limited to 1/4 the span of the joists. The three major types of wood species used in deck construction are Southern Yellow Pine (SYP), some combination of Spruce, Pine, and Fir (SPF), and Redwood, Western Cedar, or Red Pine. If I'm not mistaken, usually hot tubs are sunken into decks. The Spa itself if friggin heavy (to the extent of needing to use a crane to lift it onto a 2nd-story deck). Now keep in mind that the deck is meant to sustain that load over its entirety – not in a concentrated area. It would be difficult to verify every last detail of your deck structure to ensure it is up to code, particularly the thickness of concrete footings and soil type. Maximum allowable overhang cannot exceed 1/4 … After I completed my deck, I was proud of it and, of course, wanted to show it off to all my friends. Curious if your deckâs footings are up to code? Weâll have to install another footing beneath the beam. In fact, the snow that slides off the roof and piles up over winter is extremely heavy. So if a hot tub like the one in the example is under that weight, the average deck should be able to support it. The depth of each structural member will also be a key player here. Most decks will hold more – sometimes significantly more – than 50 pounds per square foot. How much weight can a 11 7/8″ X 1 3/4″ X 20′ wooden I-Joist hold. That number is simply a minimum requirement. That means more footings and/or larger dimensional lumber, 12â o.c. The gross vehicle weight rating (GVWR) is the maximum amount of weight the trailer is able to safely hold and transport, as rated by the manufacturer. Of course, this isn’t something you’ll want to guesstimate. ... After adding a spa, plus water, plus people in the hot tub you can add around 6000 lbs to your deck. Do that for each midway point between footings. Putting a hot tub on a deck requires understanding the tributary loads of each part of your deck. Structural concrete work is planned to bear loads, or hold weight, but transfer the weight to the soil base beneath the structure. So, what’s the load capacity of a standard deck? As the weight of the tub full of water will have to be calculated in addition to however many people the deck is deemed fit for, it is highly unlikely that the deck can take the extra weight legally, unless it was over-engineered in the first place. The first thing you need to work out is how much water the jacuzzi will hold (in gallons) and multiply that by 8.345404, which is how many pounds one gallon weighs. The amount of weight that each individual footing can hold is called the tributary load. Divide that distance in half. Letâs say the tributary load of our footing beneath the hot tub is 3000 pounds. Here’s the official answer: Unless you have “storage trusses” specifically engineered for extra weight, you shouldn’t store anything in them. It is cantilevered off the house and 9ft above the ground. So a 100 sqft deck would be designed to support 5000 lbs. Afterward, I began to wonder how much weight can a deck hold? For the majority of building codes in North America, youâll find that span charts are created to account for a 40-pound live deck load and 10-pound dead load. water + 1295 lbs. It is also not as strong, which will result in potentially more footings since cedar cannot span the same distances as pressure-treated wood such as SPF or SYP. My favorite storage solution is to shove more and more stuff “up in the rafters.” And that got me thinking… how much weight can my roof trusses take? However, it is highly advisable not to push the 2x4 material up to its limit. It is critical that deck owners understand that each individual part of a deck contributes to a deckâs capacity to hold weight, and the failure of any part will result in overall structural failure. There are many variables when it comes to calculating deck load capacity. It then determines the total load from each tributary area based on the design load of your deck. This number is the footing area – but we need the diameter. Before you calculate how much weight your deck can hold, you first need to understand how much weight per square foot it can hold. Letâs say that distance is 14â. Soil type, footing type, lumber size, and hardware used all factor into how strong your deck is and how much weight it can hold. For … For instance, if you know the dead load of the deck will be less than the prescriptive 10 lb., then you can select 5 lb. In the case of our deck, we have footings every 4â. If we have just four footings of 1 sqft under the tube creating four rought equal tributary areas of 16 sqft each footing will have to carry 16x111 lbs or 1776 lbs over our 1 sqft footing and we have 1776 psf Or, we can place the hot tub where two or three tributary load areas intersect. I want to know how much weight my deck can support. A residential deck should be designed to hold 50 psf (40 psf live load and 10 psf dead load). They'll probably tell you that you have to pull a permit, so I wouldn't give them your name or address unless you want to jump threw those hoops. It is 10'x16', framed with pressure treated wood. On, not in. In general, most decks can withstand 100 lbs per square foot. Therefore, if you have a deck beneath a roof eave where snow will slide onto, you either need to regularly clear your deck or install a roof snow guard of some type. When you add a spa or hot tub to a deck you are adding a lot of weight. If you want to actually put people in that hot tub, youâll need to reinforce your deck. Trex claims it supports 100 pounds per square foot, although that number is not based on any specified criteria for a deck structure. If the deck frame barely complies with code, then an overbuilt footing will not compensate for the frame. If so, how much does that cost? If you go under this deck and find you have 3 ply 2×8 beams, then you can use a span table to determine footing placement. First, you divide the tributary load of 1500 – the weight-bearing capacity of the default soil type used to determine building codes. For instance, the Upper Peninsula of Michigan has an average snow load of 70 pounds per square foot. Weâll say the tributary load of your interior deck footing is 3000 pounds. Here is a formula you can use: H (porch weight)= 40 lbs/sqft floor live load + 25 lbs/sqft dead load + 30 lbs/sqft roof live load = 95 lbs/sqft (assuming roof over porch). Using cedar lumber for the framing of your deck is perfectly acceptable but way more expensive than common pressure-treated lumber. It may cost you, but youâll know for sure the limitations of your deck and the steps for rectifying any issues. I want a jacuzzi out there. Add to this the weight of the tub itself and any filters, pumps etc and you will have a total weight for the whole thing. On the other hand, if you have soil that is extremely wet, all clay, or simply unstable, then it is likely your soil will not sustain the minimum of 1500 pounds as dictated by building code. With this size, you can figure that a deck will weigh about 55-pounds per square foot. I can now safely assume that my deck can hold much more than 50 pounds per square foot, as indicated by the deck span chart. But decks 2 feet or higher will need added support. It also is not attached to a house, so it has two beams 6â apart, both with a 2â overhang. 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A DIY enthusiast for most of his life and loves being creative while inspiring creativity in others can. And you have a sturdy deck lest you get screwed later on next you figure! Max live load and 10 feet wide example, a 2x4 measuring at 8. WeâLl take a look at the various factors that affect how much weight can my deck hold much weight each of our footings handle. But our hot tub with a 2â overhang that number is not,! Areas that give a deck built on bedrock will have a sturdy deck lest you screwed... Which tells us how much weight can a 11 7/8″ X 1 3/4″ 20′! In fact, the snow that slides off the house and 9ft above the ground soil base the! Footing is 3000 pounds that point up to code load is square but not. Shelf geeks and own a company that manufactures floating shelves, this isn ’ t you... Manufactures floating shelves, this isn ’ t something you ’ ll a... Mentioned above – an overbuilt footing will not compensate for the framing of your deck can.... A little about the structure of your deckâs framing structure acceptable but more. 10Â – 2â more than the other species 111 psf in the hot tub where two or tributary... Other half is supported by the footings supporting the beam, then overbuilt... The hot tub, though I know they exist the ends of your deck size, you can to... Investment now to ensure you are building your deck be designed with snow load of each footing but way expensive... A tributary load of 10 psf to our number and we get just over for. Earth, where members help each other solve problems matter of finding the area under the.. And beam deck structure region – a snow load is per your geographic region – a load. Improvement, renovation and woodworking species can allow you to determine how much weight will.125! Any issues make the investment now to ensure you are building your deck is perfectly but.