Lightweight, Chemical Free Bugshirt

Number 2 is probably your best option, go for the cheapest nylon button down shirt you can find, like at Bass Pro Shop or the like. Yes, some of these even have some kind of chemical based finish but i imagine a couple hot water washes with detergent and then a hot water wash with some soap based stuff should take out the majority of chemical finish.

On my recent AK and British Columbia trip, the mosquitoes were horrendous and my tight weaved, all linen long sleeved shirt worked well. However, ime it's hard to find a tight weaved linen shirt like that, many are at least somewhat looser weaved to maximize breathability (coming back i lost the dang thing).

If you can find a used nylon button down shirt, even if it did originally have some kind of chemical finish, chances are there is very little to none left.

I've had pretty good luck with my REI Sahara sun shirt. Use it with a head net and you're golden. Tested in Houston in the summer, and on the Little Bighorn river cutting trees. No bites. Also a damned good sunshirt! Tested during speed-week in Bonneville. No burns after hours on the salt.

Mountain Hardware Canyon (?) sun shirt is also an excellent bug shirt. Also, it has vents running under the arms instead of just on the back. I like this design when wearing a pack.

I've noticed mosquitos don't bother me if I'm wearing my Houdini jacket. They land, walk around and then leave.

Excellent responses. There is a lot of button down shirt options.

I agree, Brian, I think most (if not all) windshirts will protect against bugs. So, that begs the question, what is the most breathable windshirt? The old Houdini looks good, but I'm not sure if I can get one. Other windshirts?

Weather permitting, mosquitoes have a lot of trouble getting through two layers of cloth. Loose fitting areas will also reduce their access to your skin.

Yes, and what i've done also before is wear a thin, long sleeved non hot and very breathable shirt (like a linen, or thin cotton-poly button up) and then thrown one of those just bug net shirts (jackets? mine has a zipper) on top.

Technically they might be able to bite through both it if i held perfectly still for a long time, but with the bug net shirt being so big and loose fitting, they had a really hard time under any normal conditions, let alone hiking. That combo is probably the most breathable route you can go, however it doesn't fall into the "multipurpose" category so well.

Personally, i cannot wear a windshirt when it's both hot and buggy out, i just run too hot and it's too uncomfortable.

"2) Buy a button down (or some other style) hiking shirt. A lot of companies offer these, and they seem to be bug resistant and breathe really well. Unfortunately, many of them come pre-treated, which sort of defeats the purpose in my mind"

Last time I purchase a shirt most I saw were not pre treated with chemicals. Even those that claimed to block UV didn't use a chemical treatment to block UV. I have found mine to be very effective in blocking insects especially when I am moving.

"imagine a couple hot water washes with detergent and then a hot water wash with some soap based stuff should take out the majority of chemical finish."

I doubt washing a shirt will remove the chemical treatment. If it did peaple would probably notice and return the shirt. The chemical is applied by the manufacture with the expectation it will last and stay effective. If it doesn't they would demand a refund from the manufacture of the chemical and that manufacture of that chemical would quickly make changes to make it last longer.

You're probably right (on average) Steven. I was speaking more theoretically on that one, but it also probably depends on what kind of chemical finish we are talking about. For example, it's been talked about before that some lesser quality DWR finishes can almost completely wash off in just one prolonged and intense, torrential rain type scenario. If that is the case, imagine what a combo of hot water and detergent can do in a washer, especially if done multiple times. Almost all the tech type clothes i've seen (the ones with some kind of chemical finish) say, wash in cool to warm water, with non harsh detergent or preferably a non detergent, but mild soap based cleaner. There are probably reasons why for those specifications and warnings, to cover their butts legally if people don't do it the right way and complain when it's partially worn off or worse.

I'm not too worried about finding sun shirts that lack bug chemicals. I only mention it because some folks would recommend them if I didn't. I did make the mistake of buying one without checking, though. It said the bug stuff lasted 100 washes (or something like that). I returned it, rather than wash it 100 times before wearing.

As it is, I'm more interested in wind shirts. Sun shirts tend to be pretty heavy (although if someone mentions a sun shirt that is light, I'm all ears and am curious about the numbers). Wind shirts tend to be light, but clammy. So, basically, the lightest sun shirt or the most breathable wind shirt might be a good compromise.

As I said, some good ideas so far.

Is the Squamish more breathable than the old Houdini? I assume it is bug proof, but has anyone used it for that (or have a guess)?

I have an older Houdini and it is too hot to hike in when the wind quits blowing on trips where it is warm enough for insects to be an irritant. But I never wear it without some sort of base layer. Last week I was hiking in shorts and a REI OXT t-shirt (not sure what fabrics the T is made from). It was 50F out and the wind picked up while I was hiking on a ridge and I needed the windshirt. When I dropped down below tree line the wind was no longer a factor and I had to take the windshirt off.