Mr. Sun.

My last post was on getting my project ready for winter. A matter of equal importance is the effect of UV light on certain materials. Given that my project is taking place over a relatively long timescale, UV considerations dictated my construction agenda more than once and also demanded that some protective measures be taken. Here is a list of the materials I was/am mainly concerned with (if anyone can fill in the blanks in this list, please feel free to comment):

• Uponor hePEX - 30 days (unconfirmed)
• DOW Square Edge rigid insulation - Unknown
• #15 Asphalt felt (ASTM D4869) - Unknown but suspected to be about 30 days.
• 3M All weather flashing tape 8067 - 6 months (as per manufacturer's literature)
• Typar housewrap - 60 days

The PEX tubing that I installed was for the radiant floor heating system in the concrete slab. I'm not sure what the exposure limit for this product is but I did see a comment on a customer service forum that said the manufacturer's warranty covered up to 30 days of exposure. After the pour was complete there were just a few short sections of this pipe that protruded from the slab where the future utility room will be. I covered them with a heavy canvas bag that I made. Done.

Protecting the PEX. I folded a heavy piece of canvas in half and glued the seams together with construction adhesive. Simple.

The "Square Edge" was what I used to insulate the exterior of the basement walls and would be exposed above the grade line. I wasn't able to determine an acceptable time frame of UV exposure for this product but after observing a scrap piece that I was using for all kinds of tests, I figured that the exposure time was probably something on the order of a month or two. I base this very unscientific statement only on the fact that sometime after a month of summer sunshine my "test piece" began to become noticeably discoloured. Before backfilling the foundation I used an acrylic parging material to protect that part of the foam that would be exposed above grade and then down about 12-18" below grade. Done.

Acrylic parging will protect the exposed part of the foam from UV. The parging was extended down below grade a little to protect the foam (hopefully) from ants.

Again, I had a hard time determining an acceptable exposure time for my asphalt felt. I did find some anecdotal recommendations on some roofing forums that suggested that one month might be appropriate. Getting the felt protected from the sun was going to be a big challenge for me since I was doing all the roofing single handed. I managed to get the felt installed in a matter of days but once it was out in the sun, my belief that the felt had a limited UV exposure time pushed me to make getting the steel roof panels installed priority #1. With a lot of hustle and some long days I managed to get all the felt covered with steel in another 3 weeks. I needed a break after that.

Putting the "push on" to get my felt covered. Notice that I hadn't even finished sheathing the main floor walls. My agenda at that stage was all about making as straight a line as possible to getting the roof on. Not just to keep the rain out but to keep the UV out too.

The 8067 tape has a rather generous time allowance of 6 months. That worked well for me when I was assembling the basement walls, mud sill assemblies and main floor walls - the basement walls were covered by the floor framing within a month and the main floor walls had a roof over them within a month and a half. Here is an advantage to having an "airtight" sheathing system that installs on the interior side of the walls - most of the air-stop tape is on the inside and protected from UV exposure during construction. The one area that requires taping but that is not protected from UV exposure is the rim board assembly. The rim board assembly should be taped before the auxiliary studs are installed (for ease of installation) which means then that the tape will be exposed to UV until the auxiliary wall framing is completed and insulated. Until I have completed the auxiliary wall framing, I have temporarily covered the rim board tape with scraps of plywood and cardboard. I will switch to all-cardboard shortly since it will soon become difficult to remove the scraps of plywood from between the extra framing.

Plywood and lumber protects my tape... for now. Notice that I still need to tape the seams between the rim board, subfloor and bottom plate.

Last but not least is the Typar housewrap. I'm still not exactly sure how I will proceed yet on this front... Ideally I would insulate, hang my Typar, then install the siding one wall at a time (and no, I'm not installing a rainscreen). My problem is that I didn't get enough of my siding stained last summer to proceed in this manner - so it looks like I will either have to just put up the Typar and a "let come what may" or wait until things warm up and I can get more siding prepped. I think I will wait... I'm not into the "faded Tyvek cladding" look and also my wall system needs the siding to support the insulation and WRB since there is no exterior sheathing layer.

The moral of this story is that if you are building a house yourself or your build is taking place over a long time frame, consideration needs to be given to how some of the more sensitive materials will be protected from too much UV exposure. Protect your materials by planning ahead, getting things "covered up" as soon as possible and by being ready to "put a push on" to finish certain stages of the build in as short a time frame as possible.