If you are planning a main-level home addition, most renovation contractors you speak to will ask if you are considering a full basement under your new addition. This will be a decision based on cost, space requirement and equipment accessibility. So, the question will be, do you really need that extra square-footage, despite significant extra cost and yard disruption?
If the answer is no, you then have two less costly options. The first would be to excavate the addition area and build a concrete “frost-wall” foundation that is 4’ in height, creating a large “crawl-space”. The most common approach, but still an invasive one, likely requiring a complete rebuild of your yard.
Finally, the foundation system that Channel Custom Builders has been employing for over 15 years, wherever feasible, is very cost-effective, non-invasive and just as structurally acceptable as the methods mentioned above…the piling & grade-beam foundation. This method of construction has been successfully utilized for some commercial buildings and residentially in Scandinavian countries for over 100 years.
Beginning with engineer-stamped drawings and a relatively flat site, a series of 6’ deep piling holes are drilled 5 – 7’ apart, around the perimeter of the future addition. Concrete is then poured into these 12” diameter holes which are then fitted with rebar reinforcement and sonotube collars that form flat tops just above grade. A 3-ply 2X8 pressure-treated beam is then placed on top of the series of piles, forming the base of the 2X6 wood foundation wall. Simple, fast and with minimal yard damage!
The interior of what will be a relatively small, heated crawlspace is finished off with a row of ridgid foam frost-heave protection at the base of the perimeter wall, a black poly covering for the unexcavated ground (even over grass), followed by a layer of washed gravel. Insulating foam is then sprayed into the 2X6 foundation wall cavity. You now have a clean, dry, sealed crawlspace that can be economically heated in winter months.
Finally, everything from the floor up is standard construction, where you can now put more of your hard-earned cash into nicer finishings, rather than into the ground! Contact a Channel Custom Builders representative for more information about this little known system.