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What is the best section detail for a recessed porch over an occupied space?

emagnus | Posted in Energy Efficiency and Durability on

I am desiging a recessed porch off a second floor master bedroom. The porch/MB is above the garage.

I am looking for waterproofing and insulation details for this condition.

Thanks in advance.


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  1. GBA Editor
    Martin Holladay | | #1

    First of all, remember that the porch floor can't be at the same level as the interior floor. For proper water management, the porch floor should be one step below the interior floor; it should also be sloped to the eave. That means that you have to plan ahead when you are framing your building.

    The usual method is to slope the roof sheathing by shimming the porch floor joists with tapered shims. Then install a low-slope roofing like EPDM, properly flashed on all sides. Finally, install removable rectangular sections of flooring (a little like pallets, but made from durable lumber than can be exposed to the weather).

    If these details are new to you, you may want to hire an architect to draw up the details. Many of these roofs end up leaking.

  2. Expert Member

    Martin, it might be more accurate to re-phrase your last sentence: " All of these roofs end up leaking, the only question is when".

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