Replies

1. 
   Adam_Greisz | May 28, 2000 10:39pm | #1

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   To my knowledge neither of these products are manufactured for exterior use. Try metal stringers or p..4xs for that span. Good luck.

2. 
   Guest_ | May 29, 2000 01:20am | #2

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   Definately not suitable for exterior use unless you use TJM's Wolminized Paralam. Problem is it is mfgrd in florida and too expensive for us on the West Coast. Like the idea of a steel I-Beam, though.

1. 
   Guest_ | May 29, 2000 02:07pm | #3

   *Bill and Adam are right on. LVL just isn't made to get wet. There are treated Glulams out there, but they are pricey.

1. 
   Guest_ | May 30, 2000 06:07am | #4

   *Bill, I have used hand-picked douglas fir for exterior stringers and deck framing. I would prefer a 3x14 for a 20foot span you are talking about and you still may want one or more support under the span. If 3x14 are unavailable, pick some nice 2x12 and run supports at 8 and 16 feet. Regardless of what you use,though, I coat the boards after my cuts with a good exterior grade penetrating oil and at the cuts I rub in an ample amount of butchers wax. I then cut strips of 30# felt or weatherwatch and stick them to the bottoms of my stringers and at each tread stair cut if that is how you choose to do the treads. I would use either a galvanized screwshank 12d box or a exterior grade screw to anchor the treads. I would use galvanized hex bolts on other framing support connections and wherever wood touched wood, I would use the felt or weatherwatch between the two. I would, I wood, I wood. The best defence against problems of moisture is to build your stairs to minimize collecting water on the wood, especially between two pieces. Allow plenty of air flow. Walk good david

1. 
   Guest_ | May 31, 2000 08:06am | #6

   *David,Really good approach. I'm working on a Pau Lope stair and deck but the span is only about 7 feet. Using 2x8 PL for the stringers unnotched with 1.5" x 1.5" hot-dipped galvanized angles to support the treads. Stainless screws. Sealing the end-grain with a clear epoxy sealer.You could make it to 20' this way if you had at least one, maybe two intermediate supports. Paul Lope (Ipe) has around twice the strength of Fir but should check with an engineer. PL is also drop dead gorgeous either oiled or left natural to weather.Good luck.

3. 
   Bill_Wickert | May 31, 2000 08:06am | #5

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   I was wondering if anyone has used parallam or microlam beams for the stringers on exterior stairs. I have a project were the stairs receive extreme climate conditions (either wet and cold or extremely hot). The stairs have a 20ft span and I am thinking of using this engineered material to prevent warp and twist, but am concerned as to how it will stand up the the elements.
   I was wondering if anyone had any suggestions.

   Thanks

   Bill