Is there a best way to flash a new window with the new self adhesive butyl flashings? I have in the past started with the sill, then sides and finish with the top. But after reading on this further I have discovered that you should caulk the sides instead? Any Ideas?
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Framing the floor inside a crawlspace foundation keeps a gable-end addition close to grade.
Featured Video
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Fine Homebuilding Magazine
Fine Home Building
Follow
-
Fine Homebuilding
Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.
Start Free Trial Now -
GBA Prime
Get instant access to the latest developments in green building, research, and reports from the field.
Start Free Trial Now
Replies
the way you were doing it in the past is the way you should do it in the future..
caulk is never a substitute for flashing
All of the other windows that I have replaced do not leak, so I suppose your right! Thanks for the reassurance.
'course.. you still have to comply with the mfr's instructions to maintain your warrantyMike Smith Rhode Island : Design / Build / Repair / Restore
Mike, you said
'course.. you still have to comply with the mfr's instructions to maintain your warranty
We use Andersen products, and others also, and we find the flashing instructions from them and others wanting. If you read them I think you'll agree.
First of all, they preface, in their installation instructions, their stuff about "flashing tape" with weasel words, "This instruction step depicts one of many options for proper flashing." Then they go and show a simple tape-up, all tape atop the flanges, beginning at bottom, then going shingle-style to the top.
I have always preferred to use the method championed by AAMA and others, and copied into ANSI standards, which goes . . .
Flash across the bottom of the opening first, the top edge of the tapeflash right flush to the RO sill edge, ends 4 to 6 inches beyond each side. This differs from what Andersen says and shows, and I seriously doubt that our doing it affects our warranty.
Apply butyl sealant bead to either back side of window flanges, or at RO where flanges will bear. The choice depends on flange type . . . some folding flanges makes application of sealant to flanges more a problem. The sealant bead is always left off the sill flange or sill. Nothing there. We want any water entering to have an escape path.
Install the window. Tapeflash the sides over the flanges, shingle-lapping over the sill flash, and extending two inches past RO top edge. Tapeflash the head, covering flange and sideflash extensions.
That's it.
For a tough exposure situation, as in windows or patio doors facing weather with little to no overhangs, we use the JamSill Guard sill pan product, in addition to doing what is described above. It goes in after the tapeflash across the bottom.
Edited 3/30/2007 5:02 pm ET by Gene_Davis
gene... my weasel words still apply
<<<<<'course.. you still have to comply with the mfr's instructions to maintain your warranty>>>>
he didn't say WHOSE window he was installing...... i just wanted to make sure he covered his butt by not ignoring any mfr's instructions, especially as they apply to any warranty issue....
we often exceeed the instructions, but we seldom ignore themMike Smith Rhode Island : Design / Build / Repair / Restore