As a homeowner, if you imagine of a deck, you might tend to think the visible elements and exterior design such as aesthetics of natural wood, railings and floor boards. However, the most critical part of all decks is the part that you cannot see, its substructure.  


The substructure of the deck provides the frame work which holds up any deck. It consists everything underneath the railings and floor boards which keeps your deck safe, strong and stable. In order to help you understand how important the deck’s substructure is, some common questions below are being emphasized: 

  1. What consist the substructure of a deck?

The substructure of a deck consists of joists, ledger boards and footings. 

Footings maintains the deck’s foundation. To start building a deck’s footing, you pour concrete far down into the ground which it goes beneath the frost line (the utmost depth of ground beneath that soil doesn’t freeze during winter). Then, foundation posts are anchored into the concrete in order to provide a strong, solid and stable structure on which you build your deck. 

Joists are slices of wood which are being used to support the deck’s framework. The bigger the deck, the bigger the joist being used. 

Ledger boards are strong pieces of wood which are being used to attach the frame of your house to the deck. As a matter of fact, these ledger boards should be attached to a stable structure. The structures that should be avoided are bay windows, chimneys, brick veneers or overhangs. 

  1. What includes for a strong substructure?

There are few important pointers to bear in mind when putting up a substructure of a deck. Firstly, you have to put into consideration that you follow all the codes of the local building. That will make sure you do all the requirements in order to have a very strong substructure such as making sure that the footings have the maximum depth into the ground in order to give enough support and which the posts above the footings are correctly spaced out. Ideally, the posts are usually six feet apart, but it is as well worth checking with your local guidelines because every deck is unique. 

It depends on where you are located, you may take added preventive measures by applying water and ice shield product which will protect the woods from ice, water or moisture damage. In addition to that, flashing will also help protect your deck from any water damage. 

  1. What kinds of wood will I use to install a substructure?

Lumbers that are pressure treated are the best for your substructure. Ensure that you are using the appropriate category of treated wood.  

Having said that, lumbers that are pressure treated are considered as the best choice for building a deck substructure as well as what a oftentimes use. This is because of its affordability and load-bearing strength. 

Whenever you build a deck substructure, always keep in mind that the larger your joists are, the better and stronger your substructure will be.