WHAT ARE TUNNELS USED FOR?
Tunnels are used to gain access to the interior of your home, without having to break a
hole in your floor – much nicer! Generally, tunnels are dug to the length needed to reach under your home and measure 3 feet by 3 feet in cross section.
WHAT ARE THE ADVANTAGES OF TUNNELS?
Tunnels enable us to reach the parts of your foundation that are under the interior of your
home, without having to access it from inside of your home. Tunnels avoid the need to break holes through your slab, to tear out carpet, cut through wood or tile floors or otherwise damage the flooring in your home. When your home is lifted via tunnels you can stay in your home and do not need to remove furniture or move out.
WHAT HAPPENS TO TUNNELS UNDER MY HOME AFTER MY HOUSE IS LIFTED?
Generally, your tunnels are connected to a drainage system used to keep water from
accumulating under your home. In some cases, your tunnels will be connected to a gravity
drain, in others, to a sump pump. Tunnels should be left unfilled to facilitate any future plumbing repairs or foundation warranty work. After all, having gone through the expense of digging tunnels you might as well get full advantage of them.
WHAT HAPPENS IF THE TUNNELS COLLAPSE?
Tunnels are dug to allow pilings to be installed. Pilings are used to hold up your
foundation. Once pilings are installed your home is no longer sitting on the soil. Since the pilings are holding up your home it’s of no consequence if the tunnel walls were to crumble.
HOW DO YOU DIG TUNNELS?
The old fashioned way – we dig your tunnels by hand! This is extremely difficult work, but is worth the effort!
WHAT DO TUNNELS COST?
Tunnels typically cost approximately $85.00 per foot to dig and drain.
PRESSED CONCRETE PIERS
Holes are dug at intervals along the affected areas of the foundation. If a pier is necessary in an area that is covered by concrete then a hole must be cut through the concrete.
After the holes are dug, a hydraulic press is used to force the concrete segments into previous using the entire weight of the foundation to force the lower segments deeper.
Many concrete piers are manufactured with a 5/8 inch hole running the length of the pier so that it can be threaded on re-bar, cable, or other material that is rigid enough to prevent lateral shifting. In areas where there is no lateral shifting solid concrete segments work just as well with the added benefit of being stronger.
This process continues until the piers reach bedrock or until the friction between the soil and the surface of the concrete segments becomes so great that the weight of the foundation is no longer sufficient to press them deeper. This is commonly referred to as the “Point of Absolute Refusal.”
After all piers are pressed to the point of absolute refusal, hydraulic jacks are used to raise the foundation in multiple locations and a concrete cap and steel shims are placed between the top of the pier and the foundation. The jacks are then slowly released allowing the weight of the foundation to rest on multiple piers at the same time, insuring that the weight that each pier supports is only a fraction of the weight
that was used to press it into place.
Use of pressed concrete piers is the most popular method of foundation repair and probably accounts for more home foundation repair installations than all other methods combined. It is effective in most scenarios and is the only solution in areas where there is no bedrock or soil dense enough for other methods. It also usually costs less than other repair methods.
1. It is quick, usually 1 to 4 days depending on the number of piers
2. If installed correctly, it is extremely reliable
3. It is installed directly beneath the foundation
4. It is very cost effective
1. Installation can be messy because a large amount of soil must be removed in order to provide working room beneath the foundation. Most contractors provide sheets of plywood or other materials to hold the soil until it needs to be replaced. Any excess can be used in low areas or hauled away.
2. Plants may need to be removed, but most companies will carefully remove them and replace them upon completion.