How to Flash Windows
Over Rigid Foam Sheathing

with Mike Guertin

In this video series, Mike Guertin takes us through all of the choices and steps that you’ll need to install leak-free windows in a wall sheathed with foam insulation. Most of the details apply for doors too. From choosing the best sill-pan and flashing materials, to getting all the details just right, Mike shows you everything you need to know to keep water from slipping into your rough openings.

Start

* membership required



Self-draining Sill Pans Self-draining Sill Pans

Drain water, don’t trap it. Use sloped sills, back-dams, or both to make sure standing water doesn't rot out your framing.

Sill Pan Flashing Options Sill Pan Flashing Options

Pre-formed or site-built, pan flashing channels water out where it won't rot the sills under windows or the floors under doors.
Sill Pan With Regular Peel-and-Stick Sill Pan With Regular
Peel-and-Stick

Learn how to work with nonflexible peel-and-stick membrane to make a sill pan.
Sill Pan With Flexible Peel-and-Stick Sill Pan With Flexible
Peel-and-Stick

This type of flashing is very easy to use, but it’s more costly than the straight nonflexible flashing.
Flashing Flanged Window Jambs Flashing Flanged Window Jambs

On foam-sheathed walls, there is no housewrap to cover the flanges. Learn how to use peel and stick, housewrap strips, or pieces of roofing underlayment to protect the framing.
Flashing Pre-Cased Jambs Flashing Pre-Cased Jambs

Flashing windows with pre-applied trim can be tricky. Two good choices are site-built butyl-tape flashing and pre-made double-sided flashing membranes.
Head Flashing Windows/Doors Head Flashing Windows/Doors

At the top of the window, Mike uses peel and stick membrane to do the weather-sealing, and copper flashing for extra protection and good looks.
Counter-Flashing The Head Counter-Flashing The Head

With foam sheathing, there's often no housewrap to tuck the head flashing under. Mike's come up with a smart way to slip metal flashing into the foam.


Siding and TrimFor Pros By Pros: Exterior Siding, Trim, and Finishes

Essential Design and Installation Information From the editors of Fine Homebuilding. buy the book

Shop all Books and DVDs

Mike Guertin

Mike Guertin
Mike Guertin has been a Fine Homebuilding contributing editor since 1996. A builder and remodeler from East Greenwich, R.I., Mike is constantly testing new ideas and writing about his experience to help make our homes better and our jobs easier.



FURTHER RESOURCES ON FineHomebuilding.com

Flashing Replacement WindowsFlashing Replacement Windows
 This nearly fool-proof method makes sure that even leaky windows won't funnel water into your home

Installing and Flashing Windows Correctly
Siding alone doesn't stop water, so housewrap, sill pans, and flashing tape are essential for watertight walls

Making Sense of Caulks and SealantsMaking Sense of Caulks and Sealants
Today's products adhere better, stretch farther, and last longer, but choosing the best one is harder than ever

Flashing Windows in Rain-Screen Walls
Foam sheathing and furring strips make the wall thicker; Make sure the sill can drain and the head is tight

Flashing a Window's Head CasingAUDIO SLIDESHOW:
Flashing a Window's Head Casing
This flashing method might seem excessive until that first big driving rain

The Inspector Game:
Leak-Free Window Installation
Leaky windows waste energy and rot houses

FROM GREEN BUILDING ADVISOR

The Perfect Wall, Roof, and SlabBUILDING SCIENCE PODCAST:
The Perfect Wall, Roof, and Slab
Dr. Joe Lstiburek talks about enclosure design principles of durable, energy efficient houses

When Walls Have Exterior Foam, Where Do the Windows Go?
How to decide whether to install windows towards the inside or the outside when building thick walls

Windows, Glass, Ratings, and Installation
Good windows are essential to energy conservation and comfort

Choosing Triple-Glazed Windows
How to compare the most important window specifications: U-Factor and solar heat gain