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Community and Q&A

Choosing a New Access Door

pesc | Posted in Energy Efficiency and Durability on

I have added a whole house water shut off  valve to an exterior wall on my 1964 ranch house in Seattle. The access doors at my local stores are thin plastic. Is this OK. Do I need a fireproof door? Do I need to air seal or put wood blocks in above the access . Do I need to block critters access? I want to upgrade my air sealing and insulation in my walls  in the future. I’m not sure what is good practice.

Thank you

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  1. Expert Member
    BILL WICHERS | | #1

    If the wall needs a fire rating, then the door needs to have a fire rating too. You have to keep the entire fire barrier intact as a system, so you can't have holes in a fire rated assembly unless the "hole" is plugged or covered with some approved means.

    If this is not a fire rated assembly, then I would just build a small box under the door and seal that box to any penetrations (pipes, etc.). You'd end up with a sort of small recessed cabinet to conceal the valve. Such a cabinet style setup would provide a critter barrier and also an air barrier as long as you seal it well. Note that I would try to keep critters out of the wall itself, and not let them get into the interior spaces of the wall regardless of the valve being there.


  2. Expert Member


    As Bill said, the best practice is to place the shut off in an air-sealed enclosure surrounded by insulation. If you do this the choice of door or cover is entirely aesthetic.

    You can make your own, or buy one made for specifically for this purpose. The problem is they are designed to be put in before the valve is attached to the lines.

    1. pesc | | #3

      My Plummer did not put the pipe and shut off in a box like that. It’s just sitting inside the walls. They are coming to do other work I will ask them to fix it. What is this box called? CanI buy one at Home Depot or Lowes

      1. Expert Member
        MALCOLM TAYLOR | | #5


        Yes they are available at the big box stores and online. If you do a Google Image search for "outlet box for water shut off valve" you can see the different types.

  3. pesc | | #4

    Also is an exterior single family home wall a fire wall. It is an outside wall holding up the roof. The nearest neighbor is more than ten feet away.

    1. Expert Member
      PETER G ENGLE PE | | #7

      An exterior wall of a single family home with neighbors more than 10 feet away is most likely not a fire rated wall. Exceptions would be: the wall is less than 3' from the property line or you are in a high fire danger zone.

      With the water pipes in an exterior wall, you should make sure they are very well insulated. One option is to cut & cobble rigid foam insulation and install it behind the pipes so that the pipes are fully inside the thermal envelope. Caulk or spray foam around the edges of the rigid foam to prevent cold air leakage into the cavity around the pipes. If your location in Seattle doesn't get much freezing weather, this process may be less important. You still need some protection for occasional freezing, but not much.

  4. pesc | | #6


  5. pesc | | #8

    Thank you for this help. I am planning on makin a box by putting a block of wood on the top of my hatch and another on the side opposite the stud. I would make another box of rigid insulation attached to this box sealing it with canned spray foam and sealing around where the pipes enter the floor with canned spray foam. I’m hoping this will create an air sealed home for my shut off valve. Should I create a space between the rigid insulation and the board that seems to be behind my siding? Or should I attach it directly to that exterior side of my wall? Will this interfere with any future insulating that I do? I hope my explanation is clear. This has been very helpful.

  6. Expert Member
    BILL WICHERS | | #9

    I would put the rigid foam directly against the sheathing without an air gap.

    You don't really need extra insulation on the blocks of wood if you already have batts or some other kind of insulation in the rest of the wall cavity. You would want to air seal them though.


  7. Deleted | | #10


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