QUESTION: I have inherited a 65-year-old storey-and-a-half home in old Tuxedo from my parents. The master bedroom was originally an attached garage and about 30 years ago the slab the master bedroom sits on subsided enough the roof line could be seen to slant away from the rest of the house. My parents opted for piles to support and level the slab, which stabilized, although in hindsight a wiser choice might have been mud-jacking.
The problem I now face is that the rest of the house is apparently moving. There is evidence of tension between the master bedroom and the rest of the house in the form of severe cracking of the plaster in the common wall between the master bedroom and the main part of the house.
Also, the outside wall of the master bedroom perpendicular to the common wall has large cracks. My parents did not pile the entire home, as the cost was judged to be prohibitive.
I am writing to ask if you would recommend screw piles to support the main part of the house, assuming my analysis of the structural problem is correct. I have read that screw piles are less disruptive to install, and more economical than conventional piling.
Thanks. W. Brown
ANSWER: The remediation to the movement issues with your inherited home will often depend on the extent of the movement. If the addition and main house have separated to the point where a fairly large gap is seen in the interior or exterior walls, then further structural stabilization may be needed. If the only real result of the movement is cracks in the plaster in the interior walls, less costly and disruptive repairs may suffice.
First, get a professional structural engineer or a very experienced home inspector to do a proper assessment of the movement of the home. While a home inspector may only do a visual evaluation of the defects, recommendations may be made for further evaluation, which means calling in the structural engineer.
There are not very many professional engineers who want to take the time to evaluate residential homes -- they're usually busy enough with commercial work. For this reason, the Association of Professional Engineers and Geoscientists of the Province of Manitoba (APEGM) approached the Canadian Association of Home and Property Inspectors (CAHPI-MB) several years ago to discuss the matter. The result of this was a written agreement that outlines recommendations for homeowners with structural issues.
The agreement recommends CAHPI-MB members be initially consulted by residential homeowners when foundation or structural concerns arise. If significant structural concerns are seen during that visual inspection, the CAHPI inspector is then directed to refer the homeowner to more elaborate services by a professional engineer or geoscientist.
This recognizes home inspectors may be better suited to take a first look at home defects because of their specialized skills and the large number of properties they inspect annually. If an inspector feels there is a serious structural defect, the engineer then knows their time and expertise is warranted.
If a structural engineer is recommended and consulted, measurements can be taken and other engineering performed to evaluate your situation. From there, the engineer can determine the best course of action, if any, for your home. As you suggest, this may include recommending underpinning the entire home with poured-concrete piers, commonly called piles, or other actions to minimize the movement. If the problems are less severe, or it's decided complete underpinning is too costly or inappropriate, alternative repairs may be recommended.
Specific details, as well as structural drawings if required, can be completed by the engineer to help you when hiring a contractor to do the repairs.
As far as auger-style supports are concerned, I doubt that would be recommended. These devices are an excellent choice for moderate-cost support of small additions, porches or decks, but are not normally used for entire concrete foundations. There may be industrial-sized types of these available, but cost and installation would likely be similar to conventional concrete piers. You may be correct that they might be less invasive, but either method would require some exterior excavation outside the foundation or partial removal of the basement floor slab to access the footing to be supported.
Hopefully, the movement you're seeing is not as severe as you think, and the problem can be managed with less invasive and costly repairs.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the President of the Canadian Association of Home & Property Inspectors -- Manitoba (www.cahpi.mb.ca). Questions can be emailed to the address below. Ari can be reached at (204) 291-5358 or check out his website at www.trainedeye.ca.
trainedeye@iname.com
