I hope it has helped you learn a little about the structure of your deck and how it works. Do that for each midway point between footings. Weight. Join 6,470 readers in helping fund MetaFilter. Remember, you don’t need to be a structural engineer to determine how much weight your deck can handle. tub + 3500 lbs. Most decks will hold more – sometimes significantly more – than 50 pounds per square foot. Why? Let’s say that distance is 14’. If you are not sure if your deck is built to code, then fortunately you can still determine how much weight your deck can hold. The spa filled has 320 gallons or 2672 lbs. That number is simply a minimum requirement. What started as a small gathering ended up pretty large, and there were a lot of people on my deck. That means half of the deck closest to the house is entirely supported by the ledger board. Therefore if you have a hot tub that weighs 4500 pounds, that doesn’t mean your deck can support it since that weight is only in a concentrated area. 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. After I completed my deck, I was proud of it and, of course, wanted to show it off to all my friends. Let’s change that area of 2 square feet into inches. 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. The other half is supported by the footings supporting the beam. Let’s take a 12×10 foot deck as an example. In fact, the snow that slides off the roof and piles up over winter is extremely heavy. Luckily, we now know how to calculate those loads since we did it a few paragraphs above. 855 lb. Add that to the typical 50 a deck is built for, and you’ve got a deck that needs to hold 120 pounds per square foot. We’ll have to install another footing beneath the beam. 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. Also, deck maitnance is key (waterproofing and that kind of stuff) to prevent the wood from rotting. Aimee Ann on June 7, 2018 at 4:04 pm I have a 2nd story rec room, measuring 24×18 in … 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. If your deck is built on bedrock, gravel, or even sand, then you’ll have a higher – and potentially even a much higher – soil bearing capacity. It is cantilevered off the house and 9ft above the ground. The American Wood Council states that cantilevers are limited to 1/4 the span of the joists. for 7 occupants = 5655 lbs. If not, you’ll have to get dirty and go underneath your deck to take some measurements. When we built a deck-expansion onto our house, we also got a fairly large spa. For instance, a 3-ply 2×12 beam can span 8’ between footings when joists are 12’ long when both SPF or Western Cedar is used. Above, we calculated the tributary load of a deck, which tells us how much weight each footing can sustain. That doesn’t mean that your deck will suddenly have the same bearing capacity – it only means that your deck will not sink – ever. Today we give you the short (for us) answer to this question, How much weight can a floating shelf hold? Just as 50 pounds per square foot is the minimum weight capacity for a deck built to code, so too is soil bearing capacity. That means that the overall structure can support a load of people, or “stuff”, of at least 40 pounds per square foot on top of your deck. However, it is highly advisable not to push the 2x4 material up to its limit. You’ll also have to know the type of lumber used – in this case it is SPF since we are up north. Putting a hot tub on a deck requires understanding the tributary loads of each part of your deck. Help me make my curtains as noiseproof as possible. If the deck frame barely complies with code, then an overbuilt footing will not compensate for the frame. Before you calculate how much weight your deck can hold, you first need to understand how much weight per square foot it can hold. (8.35 lbs / gallon). But our hot tub is 3900 pounds – what do we do? Default is 50 psf which you can change. It is critical that deck owners understand that each individual part of a deck contributes to a deck’s capacity to hold weight, and the failure of any part will result in overall structural failure. We get just over 19” for our footing diameter. But what does that mean? Eugene has been a DIY enthusiast for most of his life and loves being creative while inspiring creativity in others. Next, you measure the distance between the footings. Here’s an example from deckmagazine.com: A 56-sq ft. hot tub with a dry weight of 855 lbs. 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 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. The gross vehicle weight (GVW) is how much the trailer and its payload weighs together. construction, and less joist overhang. But keep in mind those are just estimates. 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. Afterward, I began to wonder how much weight can a deck hold? Ask MetaFilter is where thousands of life's little questions are answered. I went through the permits, but was not able to find a weight rating in there. To calculate the weight of the deck, I’ll use a 10×10 deck for this example. A well-made maple skateboard deck may hold around 220 lbs, but it is still likely to snap if you land incorrectly. It may cost you, but you’ll know for sure the limitations of your deck and the steps for rectifying any issues. If structural screws were used in conjunction with deck fastening hardware, then it’s likely your deck weight bearing capacity is more than the minimum. First, you divide the tributary load of 1500 – the weight-bearing capacity of the default soil type used to determine building codes. A 3 ply 2×8 beam for a deck with a width of 10’ allows for a maximum span of 6’. It is only slightly stronger than SPF lumber or Redwood and Wesetern Cedar. However, snow load does not account for homes that shed snow off their roof onto their deck. 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. 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. 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. On, not in. The depth of each structural member will also be a key player here. The average homeowner does not have the tools available to determine how much more weight your deck can hold than the … Call your city's inspections department. 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. So a 100 sqft deck would be designed to support 5000 lbs. 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). For … However, a properly constructed cedar deck to specs of 50 pounds per square foot will be able to hold the same amount of weight as a deck that has used typical pressure-treated wood. per square foot. It is 10'x16', framed with pressure treated wood. As well, we’ll show you resources you can use to ensure you are building your deck strong enough. Now keep in mind that the deck is meant to sustain that load over its entirety – not in a concentrated area. The amount of weight that each individual footing can hold is called the tributary load. 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. In that case, designing your deck in that state for 65 pounds per square foot probably isn’t necessary as the snow would either melt or could easily be cleared before you would use your deck. That is a big range. 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. We’ll say the tributary load of your interior deck footing is 3000 pounds. 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. 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. You must use at least five framing nails to attach the rim joist to the ends of your joists. It will simply ensure that the deck does not sink into the ground. Some building inspectors may demand that your deck be designed with snow load plus live/dead loads. 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. He is passionately interested in home improvement, renovation and woodworking. Knowing the tributary load of each footing can help us determine the diameter of each footing. However, you can determine if your deck is overbuilt, which can give you an idea of how much more weight your deck can hold. There are many, many factors that affect how much weight your deck can hold. Log in to Reply. So I think I'm going to get a pro out there to spec it out. The average homeowner does not have the tools available to determine how much more weight your deck can hold than the code minimum of 50 pounds per square foot. Mind, you didn't say embedded. I've never in my life seen a sunken hot tub, though I know they exist. To safely install a roof deck, the roof needs to be able to support about 55 pounds of weight per square foot in general. Soil matters. For the majority of building codes in North America, you’ll find that span charts are created to account for a 40-pound live deck load and 10-pound dead load. With this size, you can figure that a deck will weigh about 55-pounds per square foot. It also is not attached to a house, so it has two beams 6’ apart, both with a 2’ overhang. For instance, a deck built on bedrock will have a bearing capacity of nearly 12,000 pounds per square foot. Check out this post to find out precisely what is the maximum weight holding capacity of your rod. Then find the square root, and multiply times 2. If your deck is built to code, then it is designed to hold a minimum of 50 pounds per square foot, of which ⅘ of that total is the “live” load. This number is the footing area – but we need the diameter. 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. But decks 2 feet or higher will need added support. For instance, the Upper Peninsula of Michigan has an average snow load of 70 pounds per square foot. Below we’ll take a look at the various factors that affect your deck’s strength. 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. All posts copyright their original authors. Don't get confused with what weight you might think or want to load the deck with. I have a deck. My spa started off at 600 lbs. It also risks collapsing a deck. 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. One of the best tools in your arsenal to determine deck weight capacity are deck load calculators and max span calculators, widely available online. Absolutely, but we’ve got to know how much weight each of our footings can handle. Understanding the amount of weight your deck beam can hold is, however, only one part of the equation. If you want to host a large party on your deck but still aren’t sure if it can handle the weight, it’s best to contact a building engineer. Calculating a tributary load is fairly simple if you have a standard rectangular deck attached to your house. The … and eek out a longer span. How much weight/ How many people can my rooftop deck hold? Using the example above, if you have a beam of that size built with SYP lumber, and you have a span of 10’ 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. The Spa itself if friggin heavy (to the extent of needing to use a crane to lift it onto a 2nd-story deck). For our purposes, we’ll assume our deck is 12 feet long and 10 feet wide. This is a critical number to know as a deck owner, particularly if you ever plan on putting something very heavy on your deck, such as a hot tub or gazebo. 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. Building your deck can hold is called the tributary load of each tributary area of 2 square feet by... Be a structural engineer to determine building codes load the deck for a. Will also be a structural engineer to determine that 4500 lbs is the max live load your and. 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