Thompson Basement

Tuesday, October 31st, 2017 by Gale Culbert

Challenge

We were contacted by a client in Auburn that was interested in possibly converting a portion of their crawlspace into living space. The home they had purchased was a two story on a sloping lot with the back half of the crawlspace 9 to 10 feet tall. Their growing family was in need of some extra indoor entertainment space as they already had two levels of exterior deck and the crawl space conversion would add 810 square feet of new living area.

Solution

The crawlspace area had been divided during the original construction by a bearing foundation/retaining wall. It was determined that a stairwell to the new basement would stack perfectly under the existing staircase from the main floor to the second story. There was also an area at the bottom of the new staircase that would be perfect for a powder room.

Once permits were secured we started by leveling and compacting for the new subgrade. A 20 mil poly vapor barrier was installed along with a perimeter drainage system and a sump pump basket to mitigate for possible future water intrusion, and a drainage plane of pea gravel was installed under the new concrete slab. We then installed a proprietary wall system of rigid foam wall panels with steel studs embedded that not only insulates but provides an inorganic framing and insulation system to help lessen the possibility of mold and rot. To help keep costs down drywall was used as the wall finish while a grid ceiling was installed to make possible future access to the ceiling for light fixture changes.

During the course of construction, the owners decided they wanted to finish the powder room. Since the sewer outfall was to the street above, an up flush toilet was installed to handle the waste from it and the powder room sink. We also provided access to the exterior lower deck and outdoor space. This necessitated a platform for the grade differential which also provided discreet access to the sump pump and basin.

Once complete the family now had over 800 square feet of new dry, healthy living space. They also had an additional half bath as well as another access point to the existing outdoor living areas. All carved out of what once was inaccessible and unused space.