Simonton "Wood Block" instructions

I will be replacing old double-hung wood windows with vinyl double-hung pocket replacements, probably Simonton.

Simonton's online replacement window installation instructions say: "When installing in a slope sill application place wood blocks along the existing windowsill. The blocks will help support the window and keep the sill level."

Then: Tilt the window in, "set it down on the wood blocks placed along the windowsill." "Shim the wood blocks to hold the unit secure while checking it for plumb. level and square."

There are no diagrams and no further explanations of the "wood blocks."

I can't figure out what they're talking about. Is this telling me I have to create a non-sloped shelf for the window to sit on, using a wedge-shaped wood block to basically un-slope the sill underneath the window?

Any advice would be much appreciated! Thanks.

When I installed my Simonton windows I screwed 3 small blocks on the outer portion of the sill to "un-slope" it.

They were postioned just inboard of outside edge of the window, so they were hidden by the snap-in vinyl strip provided. ~4 inches in from the left and right, and one in the center.

I used as small a block as I thought would provide support for the window so that there was more room for insulation.

When I mentioned this part of the instructions to the counter guy at the contractor-supply house where I bought the windows, he said he didn't think that most installers used the blocks. I found that if I didn't use them, I could flex the frame downward, so I opted to put them in.

Tip: If your windows came with the snap-in vinyl strip to cover the gap between the sill and the bottom of the window, spray a little WD-40 on the back of the strip to make it easier to install and adjust if required.

Thanks.

I spent some time on the phone today with Simonton customer service. Turns out those instructions I mentioned above are intended for their East Coast product line, not the West Coast ... the difference being that the East Coast line uses a separate snap-in slope sill adapter, whereas the West Cost line uses the bottom of the integrated stucco flange on the frame itself. (The side and head jamb portions of the flange are ripped at the factory if you specify slope sill.) That flange can support the outside part of the frame, making the wood blocks unnecessary. The rep did suggest installing a small piece of quarter-round right behind where the flange will go, however, to provide a backer and caulk area for the flange.

Thanks for the update.

I guess western NY is in the East Coast region cuz I got the snap-in strip.

The blocks I used provided enough of a backer for the strip that caulking was no problem.

By the way - have you looked into backer rod for the interior caulk joints? I learned about it in this forum and it was a God-send. I know I would have struggled big-time with the caulk if I hadn't of used it.

I wonder where Simonton's east coast - west coast line is...

Discovered backer rod a few years ago ... great stuff!

Reading this forum, though, I saw something I hadn't heard before: that you should use open-cell backer rod, not closed-cell, because closed-cell will outgas, causing bubbles in the caulk. I've never seen backer rod that specifies one way or the other what it is, and every backer rod I've ever seen looks essentially the same, no matter what brand.

Any thoughts on that?

My only thoughts on open cell vs. closed cell backer rod is that I hoped I used the right stuff.

I asked the counter guy at the place I bought it and he wasn't sure - no one had ever asked before.

This was a major contractor's supply house - Cook Iron Store - http://www.heavydutystore.com/About_Us_sp_3.html which has been around since 1907, so I just trusted them that it would work.

I assumed that if they carried it, then no one was complaining about it, so it must be OK. Could be a bad assumption, but at 5-6 cents a foot in bulk instead of the packaged prices I'd seen elsewhere, I put my trust in them and bought it.

I don't know how long it would take to outgas, but it's been 5 months and I haven't noticed any bubbles, although I'll admit I haven't inspected every caulk line on every window. Now you've got me thinking I should, although I don't know what I would do if I found bubbles. It's not like I'm gonna pull all the caulk and re-do it.

I think the bubbling that was being referred to was as the caulk is drying ... i.e., it would bubble and then set that way. After it has dried I don't think it's an issue.

But, like you, I've asked folks at reputable stores about this "open cell" vs. "closed cell" backer rod, and they've never heard of it, or heard of this issue. All the backer rod I've seen looks pretty much the same, whether it's the prepackaged expensive stuff or the inexpensive bulk stuff.