Why Underpinning

You know you would increase the living space of your home if you could only use the basement to create an inviting place. Your dream is to have a recreation room or additional bedrooms or a better place for the children to play. You can increase both your enjoyment of your home and its value by making better use of the basement area. Did you know you could have your current home’s foundation adjusted? The City Wide Group can safely and efficiently lower your basement by underpinning your foundation.

The City Wide Group would start your underpinning project by determining how high you want the finished basement. Once they know how much soil needs to be removed, disposal bins are brought on site and a soil removal system is established. Sometimes load-bearing walls need to be removed and replaced by a new horizontal beam and steel posts on a concrete footing. The company ensures temporary support for the house when necessary by using vertical jack supports and horizontal beams. This early stage might also involve disconnecting or suspending your furnace or boiler, and water heater. The existing concrete basement floor is then removed, leaving an angle of repose around all load bearing foundation walls. Under floor plumbing can then be removed.

Next CWG is prepared to start underpinning pockets. Underpinning pockets are specified in your architectural plans, typically in 3 separate phases, ranging in 3-4' lengths with varying depth of 18"-24" or more. The amount of the lowering depends on your requirements of the finished floor height. Often engineers require a 3-4" void between the new underpinning pockets and bottom of existing foundation, to pack "non-shrink" grout to compensate for any shrinkage in the concrete. Vibration of the concrete is often done to establish solidity and air removal to prevent any future shrinkage (in which case grout packing is not required.)

Now we are ready to install sump pumps, back flow valves, sewers, rough-ins for plumbing. Next, we install an internal waterproofing system, which consists of a 4" weeping tile system tied into sump pump around perimeter of foundation, to establish continuity and bleeding in foundation. A drainage mat (Delta MS membrane) is then installed around foundation walls, covering existing foundation and underpinning pockets, and draped over weeping tile and the gravel bed.

A 4-6" gravel bed is spread throughout basement floor to prepare for the concrete slab. At this construction stage, you have the option to have CWG install an in-floor radiant heating system connected to a hot water on demand or boiler system. A new re-enforced concrete floor (4-5" thick) is poured throughout entire basement with a smooth or rough finish as you require.

So, this describes the complete underpinning project. Before any underpinning project begins all permits must be in place along with stamped architectural/engineered drawings. To get your underpinning project underway:

  1. Contact The City Wide Group to arrange initial consultations.
  2. The City Wide Group will provide you with an architect/engineer to obtain permits OR you may provide your own.
  3. The architect will obtain permits and have them fast tracked if needed.
  4. Date is set for work to commence.
  5. We guarantee our work and you can start to enjoy your new living space.