Raising Your Home to Flood Protection Elevation: How It's Done
With April showers come May flowers, but also the chance of flooding! Frequent rain, and lots of it, can mean that your foundation is not able to withstand the extra water and potentially end up damaging not only the foundation but also the integrity of the house. There are a few different ways that your home can be elevated, whether by raising and extending the foundation or by building a new upper story. Both have their pros and cons, and we will go over exactly how this is done in the rest of this guide.
The process begins most of the time by separating the house from the foundation by raising it on hydraulic jacks. The foundation, and whatever it’s made of, then sits on temporary support while the new foundation is created.
What comes next depends on the type of foundation. For houses that are originally built on a crawlspace, they are lifted and the new foundation is created out of continuous walls, separate piers, posts, columns, or pilings. For houses built on slab-on-grade foundations, these houses are lifted together with the slab, and a new foundation is created underneath the slab. Another more extreme option is to remove the roof, build a new elevated living area inside of the home, and then leave the lower living area to be used as a garage, or storage, and access to the house. In this case, the flood protection is entirely made of the original walls.
Houses with Crawlspace Foundations
In order to elevate these types of houses, holes are made in the foundation, and beams are placed within the holes in critical points in the foundation. These beams are placed perpendicular to the floor joists, with beams placed below and perpendicular against the other beams. This creates a cradle that supports the house. After the beams and jacks are in place, the elevation begins, and once it is at the appropriate height, the foundation will be filled. Holes will be left within the foundation so that floodwaters can move through and equalize.
Houses on Slabs
Houses on slabs follow some of the same points - they get raised with hydraulic jacks and beams. The differences come in when designs and constructions make lifting slightly more difficult. Given how slab homes are created, it is better to elevate the two together. However, this can be slightly more difficult as lifting the slab requires precise measurements and being sure that the slab will not crack. Placing the beams requires that trenches are dug around the house, the beams placed in those holes, and then allowed to go through the lifting process.
What To Consider
When doing any kind of flood protection elevation, you need to consider what the base flood elevation is. Any raising of the foundation needs to be done to sit above that level. Otherwise, you will not completely protect your foundation and your home from flooding. How much you have to raise the home can range in various amounts. Sometimes, you have to raise the home only three to four feet, which allows you to rearrange some shrubbery and regrade only slightly. If you have to raise the house over four feet, it is generally better to create another story and use the lower level as storage or a garage.
It is important to know all of the details before you decide to raise your foundation. Sometimes, it can be quite a process - even more than you might have thought if you have to add a whole story! In the end, it is important to have someone do the research ahead of time to tell you exactly what you will need to do, and how. Let Allied help you with all of your house lifting needs, and be sure to reach out for a free estimate today!