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Community and Q&A

Summer seasonal home construction and codes

lguerci | Posted in GBA Pro Help on


I own a summer cottage on Lake Ontario which is sited so it is at the vortex of year round wind (and accompanying rain and snow depending on the season) conditions, which are especially fierce in the winter. The water for the whole community is turned off from early fall to mid-spring. When we bought the cottage, it had shiplap siding and 2 x 4 walls, ceiling and roof spaced 21″ on center with no interior finishes and old double hung windows. Any moisture which came in through the walls and roof just evaporated. Unfortunately the foundation had basically disappeared below grade and the walls were bowing so much that we eventually had to so re-build. That is where the nightmare began.

The contractor, who had glowing references and who had little supervision since I live 400 miles away, did just about everything wrong that could be done- substandard framing, no flashing on the windows, incorrect perimeter drain installation, tar paper valleys on the roof, and on and on. This was a time and materials job with little budget pressure so there was no reason to skimp on quality. WIthin three years, the entire place had to be taken apart because of water infiltration and mold. Even the framing had to be replaced section by section because the framing was so weak and punky from the water.

If I had not had to meet current building codes and could have essentially build an old fashioned summer shack with no insulation, the shoddy construction probably would have lasted many years just like the poorly built original.

The cottage is all back together with spray foam insulation, properly vented siding, new perimeter drain, and marvin clad windows, etc. I am concerned about the building envelope being too tight and moisture inside coming through the concrete slab which is close to the water table. The contractor has gone out of business and I really don’t know what he did with the slab, but I can be sure that there is not insulating foam. What would be recommended for insuring that I have proper air flow for a place that is closed up from September to June?

Now I am about to work on my uncle’s adjacent cottage and don’t want to make any mistakes this time. What would be the best building structure be for a small summer-use only cottage under fierce winter weather conditions.

Thanks for any suggestions.

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  1. user-659915 | | #1

    Are there are other homes in the community that have been rebuilt tight like yours? Do their owners have any experience to share? If not perhaps you should wait a while before starting work on your uncle's cottage. It may take a few seasons to get the full value of learning from your own mistakes.

  2. BobHr | | #2

    Most of the moisture in a tight home is from occupancy, bathing, cooking, breathing, etc. In an unoccupied structure you will not have those sources to deal with. Very cold air also has very little moisture. I doubt there would be much risk. I assume electricity is available year around. You could use an exhaust only ventlation approach. set on a time to run a little bit each day.

    As for any new construction you could insulate underthe slab and place poly so the concrete is poured directly on the poly. Though being a seasonal cabin is may not be worth it to insulate the slab.

  3. GBA Editor
    Martin Holladay | | #3

    If I were you, I would keep my eyes open, but I wouldn't worry. It doesn't sound like your renovated summer home has any problems. If you see any signs of a problem, then you can address it.

    In general, there is no need to ventilate an unoccupied house.

  4. lguerci | | #4

    Thanks for your responses. I will plan to insulate the slab in the new construction in case the time ever comes that the summer community allows year round living and perhaps get a humidistat to see if there are moisture issues in the already re-renovated cottage. I appreciate everyone's comments.

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