Hi,

I have a question regarding material choice and/or material treatment. I have a client who would like us to build him a large swimming pool enclosure. In addition to a challenging span, 30’, I’m concerned about the humid environment. The architect and general contractor are aware of my concerns, but I don’t get the impression that they appreciate that this could be a difficult issue over the life of the building. The available local species are eastern white pine, hemlock along with red and white oak. Hemlock and red oak are not really considerations. I’d prefer white oak, but I’m not sure we can handle the pieces. If I use eastern white pine is there some finish treatment I can use to help seal the wood and provide additional resistance to moisture?

Also, what other species might be practical to use on the east coast?

Thanks, Pete

My recommends are as if I were building such a structure for myself.
Post bottoms and all cross grain cuts sealed immediately after cutting. Post bottoms are further protected by ice dam rubber (bitchithane) and they sit on short piers so water cannot pool around the posts.
You can use a quality wood deck water sealant on all exposed surfaces applying two coats (Olympic would be my choice). Spray and/or roll it on. An alternative would be water based external polyurethane.
Use only quality coated metal fasteners.
expensive but worth it use composite windows from Anderson.
Your cost to build just went up.
Good luck.

Be careful of what you treat timbers with (assuming you are using green timbers) you don't want to lock water in the wood.

I'll second Emmett's coment on sealing end grain, a small tub of Anchorseal has become a standard part of my timber framing kit.

I'd say go with the White Oak if at all possible unless you've got the budget for reclaimed Chestnut, there are always ways of handling more weight. My wife and I installed our entire sill structure including a 20' 8"x9" Hickory sill (~630lbs.) up onto the foundation by power of lever, roller and hand.

If you don't mind me asking, where in CT are you? We're in Warren which is in western Litchfield Co.

I have worked on a handful of timber-framed pool enclosures. My recommendation is to make sure that the pool has an automatic retractable cover and that the space is provided with a properly sized dehumidification system. Obviously, keeping the posts up off of the deck is important too.

Thanks guys. That’s the type of input I was looking for.

The architect and general contractor have identified that the pool will have a cover and a HVAC system/dehumidifier will be provided. My concern is that designing an appropriately sized system may be a challenge and that the timber will be exposed to higher moisture levels than typical. I’d like to be able to provide a frame that can accommodate these potentially higher moisture levels. We usually seal/wax our tenons and we’ll make sure all the end grain is sealed and the posts will not be in direct contact with any concrete.

I’ve looked at some of the sealers/stains that are available for log homes. The concern regarding ‘trapping moisture in’ by applying a sealer is a good point and I plan to contact the sealer/stain manufactures to get additional input.

I realize that you can always come up with inventive ways to handle larger pieces, there is a very nice thread on ‘going it alone’. My guess is I’d need an 8x10, or larger, piece 30’ long. Based on the way we work and the material we typically deal with, I know my guys would have a stroke if I told them we were going to work with 8x10x30 white oak. We do work with larger pieces, I just think the 30’ oak piece is beyond our capabilities.

Chris,
What type of material did you use for the pool enclosure(s) that you have been involved in?

Raphael,
I’m located in North Stonington, CT.

Any other thoughts would be appreciated.

Thanks,
Pete

When I was landscaping in NY we used a whole lot of Eastern Red Cedar and occasionally Black Locust. Locust isn't going to reduce your weight much ~5lb./cu.ft. per the tables, it always seemed astronomically heavy when going from standing dead Cedar to green Locust.

Pete:
Any type of finish only slows the migration of moisture, so the owner needs to maintain the average moisture content of the room below that which would support growth of mold etc. The designer of the mechanical system should be able to accomplish effective humidity control. Put a disclaimer in your contract that states something to that effect. I assume that there will be other non-structural materials in the room that would not fare well at excessive relative humidity. Air leak sealing is also very important in the building envelope.
One frame was salvaged and regraded material with hidden steel reinforcement, others were most often white pine.

Other timber options to consider that our local to our area (SE CT). Black locust, Sassafras, white cedar (juniper), tamarack.

While I was paying a visit with an engineer to discuss a timber frame pool enclosure, he was answering phone calls from his guy in the field who was surveying a failed SIPs panel system.
The failures were due to installation mistakes and the installers had apparently done everything they could to insure failure..but! It was a bit like looking over frostbite photos while planing an arctic trek (or Antarctic if Gordon McD reads this).

So...taking all this as a providential reminder to pay attention to detail I recalled this thread and thought I would revive it and add a quest for combined wisdom regarding SIPs detailing in humid environments.

On the other hand I could spec a vulcanized rubber enclosure.

And yes the pool will have a cover and there will be a dehumidifier