Best Foundation for Decks or Bump-out Additions

Common Foundation Types for Decks in New Hampshire

When it comes to choosing a foundation for your deck or bump-out addition, there are really only a few options which are accepted by regional building codes. While bump-outs can involve the forming of poured concrete walls or slabs, for the most part the traditional way to go is poured concrete piers. This is also true for decks or sunrooms. Another growing trend in the New England area, and around North America, is the use of helical piers. 

Reinforced concrete has been used in construction since the 1800s, and today is still widely used for most home foundations in New Hampshire. Concrete pillars, or piers, are very common for supporting decks, sunrooms or small structures. The concrete piers are prepared by;

• excavating down below frost line levels
• sliding in a form of some kind (sonotube)
• backfilling the form and then pouring in the concrete

Standard acceptable depths for this process are generally 4' in New England. The further north you go though, as temperatures drop and the frost line gets deeper, more depth is required for the piers. This is to avoid heaving as the soils freeze and unfreeze, making the ground unstable.

While concrete pillars are relatively effective and are widely accepted by building departments, they do have the following drawbacks;

• can be prone to frost heaves if not placed deep enough
• requires excavation or digging, can be messy (displaced soil needs to be removed or dumped)
• can settle over time in shrinking or unstable soils
• very labor instensive, man hours adding to the overall expense
• concrete needs time to cure, cannot install posts same day

The Benefits of Helical Piers for Decks and Sunrooms

The idea of helical piles or piers has been around for quite some time, though use of them for supporting decks or similar structures in the New Hampshire area is relatively recent. Concrete pillars have been the norm for contractors and homeowners, but as the benefits of helical piers and helical screw piles become known, more and more people are opting to use them. 

Helical Piers/EZ Post Pros;

• installed well beneath frost line depths, will never be impacted by frost heaves
• will never settle, so considered a permanent foundation
• easy, clean installation (unless there are large rocks/boulders in the soil)
• can support heavy structures
• galvanized steel resists corrosion
• can build on the helical pier same day, no waiting
• less labor intensive, can be less expensive than concrete

Cons;

• requires machinery, can do slight damage to landscaping
• tough to install in rocky soils

EZ Post helical piers are designed to accept standard steel support brackets for 4x4 or 6x6 posts, and these specialized piers do away with weather delays because they can be installed regardless of temperature and precipitation conditions.

As with all home repair or home addition projects, the work put into the home is an investment. When deciding on whether or not to go with helical piers or standard concrete piers, consider the pros and cons of each application and decide which is best for your project. If time is not a factor, and you are able to save some money by digging the holes for concrete pillars yourself, concrete piers may be the best option. However, if you're looking for a long term, permanent, cost effective solution, then EZ Posts helical piers should be your go to option.