New Wichita codes proposed for slab construction
A seven-month city investigation has determined that new houses in a crumbling southeast Wichita subdivision met building codes.
But city officials acknowledge that a group of houses in the Maple Shade subdivision at Harry and Webb were built on unstable ground and plagued with a variety of drainage problems, issues unregulated by the city building codes.
Until now.
A city task force on slab houses will ask the City Council early this fall to enact tougher building codes to limit the exposure of buyers of slab houses to a repeat of the structural problems that caused a half-dozen Maple Shade houses to crack apart.
Slab houses are built on concrete slab foundations without a basement.
The new codes, if approved, will bring Wichita in line with similar codes in several Kansas cities.
No action is planned against the license of Maple Shade builder Clint Miller, Kurt Schroeder, the superintendent of the city's building inspection office, said Thursday.
Schroeder and Wichita architect Tom Compton, who led a task force looking into the Maple Shade housing failures, said they have a set of tighter building codes for slab houses that should protect consumers.
"It's kind of a perfect storm scenario," Compton said about the problems in Maple Shade. "Everything went wrong that could go wrong. It didn't mean that the whole system was broken, but it means that we probably need to address it more formally so that everybody knows what the rules are."
Compton said he didn't do any forensics on what happened at Maple Shade. But he pointed out that poor drainage, fill dirt and clay soils were probably primary factors, which the new codes will address.
"A lot of what you see is kind of middle of the ground, kind of what's realistic and what makes sense for the builders," Compton said of the proposed rules. "But it's not a Sherman tank.
"This document plugs a lot of those holes," he said. "It doesn't get rid of it. Nothing is going to absolutely get rid of it."
'On the mend'
The proposed codes were praised by one of the Maple Shade homeowners and a prominent Wichita-area homebuilder. Several homeowners in Maple Shade spent tens of thousands of dollars to repair their houses.
"It seems like it was a long time getting done," said Betty Wiens, whose $141,000 Maple Shade house required more than $80,000 in repairs to become livable again.
"It should give a person buying a slab home more confidence."
Wiens said she draws some comfort from the move by city officials to tighten their control over soil quality in subdivisions.
"I get satisfaction that bringing attention to the awful condition of some of the houses Clint Miller built will have new standards for any built in the future," she said.
However, Wiens said Miller's brother, Steve, the subdivision developer, deserves credit for addressing some of the housing problems.
"I am hoping Maple Shade is on the mend and will flourish in the future. It really is a good place to live and the neighbors are great," she said.
Steve Miller said that one house, owned by Carol Poe, has been repaired and another homeowner, Chelsee Anderson, has taken another house in the subdivision.
"We're working on it," he said. "With the tough market, it's been tough to get back there and work on it, but we're trying."
Steve Miller said engineers have found some settling at Steve Garner's Maple Shade house, but he doesn't think the house has been compromised.
Local homebuilder Craig Sharp reviewed the proposed changes for The Eagle and agreed with Wiens.
"These new practices seem to be in line with covering the issues that slab homes have had over the years and particularly most recently with the Clint Miller homes," Sharp said.
"These new requirements will make sure the soil is tested and that the footings are deep enough, which definitely seem to be reasonable and necessary."
The new standards
The proposed standards for residential foundation and slab-on-grade houses, according to city documents, include:
* Soil testing and analysis at any building site, with the results provided to city building officials for permitting purposes.
* A plasticity index testing, a test that determines the potential for expansion and movement of soil over time based on the moisture content of the soil and soil type.
The severity of the new codes that homebuilders are required to meet will be determined by the results of those tests.
If the plasticity figure is greater than 45, the footings, foundation and slab systems must be designed by a Kansas-licensed structural engineer to obtain a building permit.
* Steel reinforcement bars and/or wire mesh will be required in all slabs. Fiber reinforcing material — such as the type that broke apart in Wiens' house — may still be used, but only in addition to required steel reinforcement.
* Specific materials and criteria are established for the fill dirt directly beneath slabs, as are appropriate depths, depending on soil analysis and required minimum footing and foundation design.
* Foundation and surface drainage design and maintenance are emphasized, to minimize the potential for foundation/slab damage from water.
* An additional city inspection in the building process. Inspectors will check and verify required steel reinforcement and under-slab material placement before the concrete is poured for the slab foundation.
How it would work
When a builder prepares a site for construction, he or she would have to dig up two soil samples from opposite corners of the building footprint.
The 8- to 12-ounce soil samples would be taken from about a foot below the surface and placed in sealed plastic bags for professional analysis.
Soil engineers would determine the plasticity index of the soil, which tells the builder what kind of soil it is, how likely it is to expand and contract and how deep the house's footings will need to be to comply with the city code.
It costs roughly $200 to have a sample analyzed, but it depends on the sample and whether the builder digs the soil and delivers it or has the soil engineer come to the site.
Builders would submit the test results with their building permit application.
That's a big step away from the status quo, which requires no soil testing.
But it remains up to the developer, builder and homebuyer to do as much research as they can to make sure they're not building a subdivision on unstable fill dirt that may have debris or soil types that are more likely to settle and cause cracks in slab foundations.
If someone is caught trying to deceive city inspectors, the city could make a case to have the builder's license revoked.
City inspectors will check footing depths and locations.
The city wouldn't allow using just fiber materials to reinforce the slab — it would require steel rebar. Compton said fibers are only meant to control shrinkage.
"It helps the slab not crack as much," he said. "But it does not reinforce the slab. Steel enforces slabs."
The city has always inspected footings and foundations. But the proposal would require another inspection to check the drainage, sand and rebar that is laid down before contractors pour concrete.
That could add to inspectors' workloads — although residential building has slowed with the economic downturn.
Schroeder said he doesn't yet have an estimate of how much the extra inspections could cost the city, and the task force doesn't have an estimate of how much the stricter regulations will add to the cost of an average slab foundation house.
But deeper footings, more inspections and more concrete will clearly increase the cost, Schroeder said. He said that many builders were already following the proposed guidelines.
The foundations and slab task force is also stressing that builders strictly follow subdivision drainage plans, which was a major part of the problems in Maple Shade.
When too much moisture mixes with clay soil, it heaves and can cause cracks throughout a house, including foundations and walls.
"While many uncontrollable environmental factors influence soil conditions, including weather, vegetation and exposure, poorly sited buildings with poor drainage plans are the most susceptible to water and foundation damage," the proposed soil standards guidelines say.
This story was originally published July 31, 2011 at 12:00 AM with the headline "New Wichita codes proposed for slab construction."