Boodovaa reached out to Mammoth Building Supplies to find out more about deck failure and share their expertise on prevention and repairs. We hope this information will be useful to understand deck building and failures.
What are the signs of potential deck failure?
There are many signs of a potential deck failure from using the wrong bolts to rotten wood. Here are the most popular signs of a deck failure.
1.Using the wrong hardware is one of the major reasons why decks fail. Here you can see the screws that were used, one bent and the other totally broken off.
2. Water damage is another big reason why decks fail. When deck builders/DIYer’s mount the ledger to the house, they often do not use a flashing to protect the house rim joists or they do not use a spacer between the ledger and the house for water drainage.
3. Mounting a ledger board into an OSB rim joist is another reason why decks fail. Deck builders/DIYer’s screw the ledger board into the house not realizing that the screws are only going into the OSB and not into a load bearing support.
4. Cheating!!! This is another reason why decks fail. Deck Builder/DIYer’s use what they have that makes the job easier for them. Here you can see that someone used a carriage bolt that was too short and cut out the support from the ledger board which has now weakened the ledger board dramatically.
5. Nailing a ledger board into a house is one of the most insufficient methods of attaching and carrying the load of any deck. Nails do not have enough shear strength to hold up a deck.
Building a deck is something most home owners would attempt to do themselves as it is one of the least complicated projects around the house…so they think!! Building a safe strong deck takes knowledge and know-how, but we cannot stop a homeowner from building on their own home. This is one of the reasons why we developed the M3500 Foundation Deck Bracket. Knowing how to mount a safe and strong ledger board is a very critical step when building a deck that is attached to the house. The M3500 takes the guess work away, by just following the mounting instructions and following the guidelines for the correct number of brackets that must be used.
Throughout North America, the way decks are being supported is changing. More and more municipalities are asking for ledger board weight to be transferred directly to the foundation because the foundation is the strongest part of the house. Mammoth Global Inc. has seen this coming 2 years ago and that is why we developed this bracket in 2016 and has been testing it ever since. The M3500 was designed, engineered and is manufactured in Canada. (This is a big deal to us here at Mammoth Global Inc. as we want to support our economy here in North America.)
What is the Mammoth M3500 Foundation Deck Bracket?
The M3500 is constructed of 3/8″ 50W structural steel which is the same steel used to build structural bridge members. Our PATENT PENDING engineered design uses center point load technology. The side flanges ensure a correct installation of the deck support post to ensure the proper weight distribution over the center supporting flange.
With the introduction of heavy composite decking materials more load is being placed upon the ledger board of decks. Typical current installations is to bolt or screw the ledger board to the side of the house. Quite often the bolts or screws miss their intended connection or are put through a veneer of brick or siding. Over time these connections deteriorate allowing the deck to fall off with the severe potential of personal injury. The M3500 will eliminate these potential problems by transferring the entire ledger weight load to the house foundation. The M3500 is a solution an age-old problem of falling decks. Deck safety is a priority. 
What is the advancement in terms of building code for deck support?
Building departments across Canada and the USA are beginning to mandate that all ledger board weight now be transferred directly to the foundation of the house. All decks will now be required to have additional support via a 6×6 PT post into a foundation attachment. The Mammoth M3500 is the solution to this issue, an easy 15 min install and it will save time and money.
How to install Mammoth M 3500 and what kind of bolts shall be used?
Our supplied custom grade 8.8 sleeve anchors are rated for 3000 kg or 6600 lbs each. Each M3500 comes with 4 sleeve anchors.
Load Calculations:
Calculate approximate load weight
Wood Decks:
Dead Load = Approx. 40lbs / sq ft
Live Load = Approx. 150lbs / sqft
Composite Decks:
Dead Load = Approx. 60lbs / sq ft
Live Load = Approx. 240lbs / sqft
A/ 2 x B x load= Load on Ledger board
Recommended space for M3500 is every 8′ with a 10″ double ledger boards.
How much it may cost to strengthen the deck using M3500?
Each M3500 Foundation Deck Bracket cost $89.99. Most decks would use approx. 2-3 brackets depending on the width of the deck. Each bracket is comfortably load rated for 3500 lbs and the recommended spacing is 8′ to 10’ intervals depending on your floor joists.
For more details visit https://www.boodovaa.com/listing/mammoth-building-supplies/
