Window replacement with a rot repair site

Summary: For Travis Brungardt and Joe Cook, co-owners of Catalyst Construction, a call to a customer who began investigating some stains and peeling paint under a bedroom window revealed other underlying problems. After peeling off the cladding housing, the two discovered that the house also had none water repellent barrier behind the paper-backed bar that held the stucco. Through this repair job, Travis and Joe had to clean up the rot, put in new windows, and prepare the new wall for the stucco, which wasn’t a cheap repair.

My business partner Joe Cook and I were originally called to our client’s home to examine some stains and peeling paint under the bedroom suite window. After looking around, we found that the four-part casement window was leaking and should be replaced. The work basement directly below also had the same stains and peeling paint below, as well as stains above it on the wall-to-ceiling junction – likely evidence of the window leak above.

Due to the close proximity of the two windows and the relatively easy interchangeability of the lower element, the customer agreed to exchange the two wing elements at the same time, so we ordered two new wing elements from Marvin. In view of the poor accessibility and the considerable size and weight of the quadruple windows, we have planned two full days for the exchange. With the windows and everything we needed for on-site installation, we felt secure in our process and the time that was available. After we had covered the bushes with tarpaulins and set up the ladders to pull off the window cladding, things unfortunately quickly went out of joint.

More than a new window. After removing the panel, we found that the damage was worse than we expected. The original builders tried to seal the windows against water ingress by taping the nail flange over the nail flange, but doing little to prevent water from entering the opening and rotting the jacket. We tore off the stucco to get to the rotten casing and frame.

Remove stucco

Two ways of getting water in

The bedroom window head flash appeared to be free of defects or flaws, so we attributed most of the leakage to the three gauze connections between the four wings. These hollow channels seemed to direct the water inward to saturate the exposed OSB underneath. But when we pulled the 5/4 in. LP SmartSide fairing enclosures we uncovered a major problem – this house didn’t have one water-repellent barrier (WRB) behind the paper-backed bar that held the stucco. Joe and I immediately worried about a lot more than badly flashed windows.

Cut out rotten wood from the windowCut out the rot. Fortunately, the socket and king bolts that flanked the window were still in good condition so we could use them to prop up a new LVL head. We cut back the top panels on good wood with a jig saw to make room for an 11-7 / 8-inch deep LVL.

The grade D construction paper that is part of the paper-backed strip that is attached to the stucco is intended to serve as a bond break, not a water-repellent layer. Ideally, it will ripple when the wet stucco is trowelled onto the molding and will remain so even after the stucco has dried. Behind that there should be an additional layer of construction paper or other water-repellent material that serves as the actual WRB. Together, the wrinkled first layer and the second layer form a drainage and air space that promotes drying. An even better arrangement would include a drainage matrix or air gap between the two layers to improve drainage and drying; such a gap is necessary in humid climates. (For more information on creating this drainage level, see “Rain protection products for stucco installations”) Without WRB, the wet stucco and the paper give off their moisture directly to the OSB. As feared, we found that OSB was absolute toast in a number of areas. When we peeled it off we found mold on the kraft paper siding of the insulation and the back of the drywall, both of which were easy to dispose of. Unfortunately we also found heavy ones Frame rot.

Every morning during the project we noticed severe frost on our materials and ladders, which quickly turned to liquid water as soon as the sun fell on the construction site. We suspect that this regular wetting of the stucco further helped wet the rest of the assembly, even though the customer refused to allow us to examine the extent of the damage to validate our guesses.

install a new lvl headerNew header and cripple. When the cover plates were cut back, the new LVL attachment was placed under the existing hinge beam. New cripple tunnels under the LVL have a bead of construction adhesive on the inside edge to attach the drywall.

Carry out repairs

Applying tape to create a continuous sill and pan flashingPrepare the opening. Poor window indicator details added to the sad condition of this wall. We used Zip System stretch tape to create a continuous rocker panel to protect the wrap and frame.

On the second day, with a significantly larger scope of work than the previous day, we removed the lower window unit and removed the OSB from the sockets and kings on both sides. With the window open, we could see that the window sill, cripples, and floor panel under the window were completely rotten, so we removed the stucco under the window down to the floor to replace the frame. Fortunately, the Jack and King studs that support the header were in much better shape, and we only had to splice on a short section at the bottom of one side.

After replacing the rotten frame with new stock, we installed Rockwool insulation and Zip system jacketing. We flashed the opening with Zip system stretch tape and sealant and installed the Marvin windows on some 1/4-inch. Washers under the troughs and outside corners. With the lower window unit, we temporarily attached pieces of OSB to the headliner to protect our work as we walked up the wall. With no realistic hope of completion, we decided not to remove the bedroom window and instead focused on tidying up and preparing for the next day.

Install windows with flashing tapeSeal the flange. After the window opening was prepared, we installed the lower window. A generous bead of sealant on the nail flange prevents water from entering. After the window was completely nailed, we covered the top and side flanges with tape and rolled it up for a strong connection.

Joe drove several structural screws through the top and side posts of the existing top window to secure it to the head and socket studs. We removed the fiberglass insulation, the moldy backing paper on the drywall, and the rotten cripples and the window sill under the upper window. Then we started reframing, which kept us busy until the end of the day when we had to put up a tarpaulin for two lost working days due to strong wind and snow.

remove rotten frameKeep going up. After the frame over the lower window was rebuilt, insulated, and paneled, we moved on to the upper window. We removed the lazy frames and added a receptacle under the window so we could splice the cut wire and run it through new cripple bolts.

We returned the following Monday to remove the upper window and install its replacement using the same procedure as for the lower window unit. It was much more difficult to install this window from ladders so we removed the sashes from the frames and reinstalled them after squaring the unit.

install new insulationNew insulation. The fiberglass mats under the windows had mold and water damage to the kraft paper siding, so we replaced them with mineral wool. We like nonwovens made from mineral wool because they are stiffer and make a tight fit easier.

We stapled the flange plane over the top, and with the unit in the center of the opening, we drew diagonal measurements and underlaid the frame until both diagonal measurements were the same, which suggests the window was square. Then we nailed off the flanges and reassembled the two fixed and two control wings. Then we glued the window and the remaining zip jacket seams to the existing OSB. We had an area of ​​existing OSB that we weren’t convinced of as it disappeared behind the stucco space. We installed new 5/4-inch. LP SmartSide molding around the windows and replacing the molding above the window to prepare everything for the stucco crew.

Roll seam tapeKeep dry. We used a Zip system wrap with its built-in water-repellent barrier to protect the house and keep things dry until the stucco is put back in place. Rolling up the seam tape is key to a good bond with the tape.

Move inside

After our work outside was completed, we moved inside and cut the new window with post extensions and cladding to match the existing one, spitting out the few defects in the Drywall, and left this to the customer to paint. The customer also decided to hire a plasterer directly, which enabled us to limit our two days of planned work to just one and a half weeks with delays due to weather conditions. It appears that the cheesecloth joints on the windows were leaking, but the original builder’s decision to use paper-backed battens directly over the OSB without a second layer only exacerbated the problem and potentially affected the jacketing in other areas.

Window after repairLike it never happened. After mending the drywall under the window, we paneled the opening and finished our part of the job. The customer would later repaint the room and hire a plasterer to touch up the stucco we had removed for the repair.

The owner of this home has chosen to fix things when they fail rather than fix all of the potential bugs at once. As you can imagine, this wasn’t an inexpensive repair, and it will likely cost tens of thousands of dollars to repair and set up the assembly to properly manage moisture ingress.

Travis Brungardt is a co-owner of Catalyst Construction in Prairie Village, Kan. Photos from the author.

lazy to the core

From Fine Homebuilding # 304

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