RELIABILT New Construction Windows
RELIABILT new construction windows have a nailing fin for mounting directly to wall framing before siding is installed.
RELIABILT new construction windows have an integral nailing fin (flange) that fastens directly to wall studs before siding and exterior trim are applied. This is the correct type for new builds, additions, or situations where you are replacing the entire window frame (not just the sashes). Priced from $99 to $300+. Available in the same 3201 and 3500 series as replacement windows with identical glass and frame specs.
New Construction vs Replacement
| Feature | New Construction | Replacement |
|---|---|---|
| Mounting | Nailing fin screws to studs | Insert fits inside existing frame |
| When to Use | New builds, additions, frame removal | Upgrading existing windows |
| Exterior Work | Yes, siding installs around the fin | No, fits inside existing opening |
| Glass Size | Slightly larger (no insert frame) | Slightly smaller (fits inside old frame) |
| Price | $99 - $300+ | $89 - $300+ |
How to Choose a New Construction Window
Sizing: New construction windows are ordered based on the rough opening size in the framed wall. Standard rough openings are framed 1/2 inch wider and 1/2 inch taller than the window unit. RELIABILT new construction windows are available in standard sizes from 24"x36" to 48"x72" across single hung, double hung, and sliding styles. Custom sizes are available through Lowe's special order program.
Energy ratings: For new construction, energy codes in most states now require minimum performance standards. The RELIABILT 3201 Series meets Energy Star requirements for northern and north-central zones. The 3500 Series meets all US zones and exceeds minimum code requirements in most jurisdictions. Check your local building code for the required U-factor and SHGC before ordering, as inspectors will verify compliance.
Climate considerations: In cold climates (Zones 5-7), the argon-filled 3500 Series is the better investment because it significantly reduces heat loss through the glass. In hot, sunny climates (Zones 1-3), pay close attention to the SHGC rating. A lower SHGC blocks more solar heat, reducing air conditioning costs. In mixed climates, a moderate SHGC balances winter solar gain with summer heat rejection.
Flashing compatibility: New construction windows require proper flashing tape and sill pan integration with your house wrap or weather-resistive barrier. Before ordering, confirm that the nailing fin profile on the RELIABILT window is compatible with your chosen flashing system. Improper flashing is the leading cause of water intrusion around new construction windows.
Ordering in bulk: If you are building a new home or addition with multiple windows, order all windows at once from the same production run. This ensures consistent color matching across all units. Lowe's offers contractor pricing for bulk orders, which can provide meaningful savings on larger projects.
Common Problems and Fixes
Condensation between panes: Moisture trapped between the two glass layers indicates a failed IGU (insulated glass unit) seal. This is a manufacturing defect, not an installation issue. The glass unit needs replacement. RELIABILT covers this under the limited lifetime warranty. Keep your Lowe's receipt for proof of purchase.
Water leaking around the frame: Water intrusion around new construction windows is almost always a flashing problem, not a window defect. Check that flashing tape overlaps correctly (shingle-style, with upper layers overlapping lower layers). Verify the sill pan slopes outward. If water enters above the window, the head flashing may be incorrectly integrated with the house wrap.
Drafty seals: If you feel air around the window frame after the wall is closed up, there may be gaps between the window frame and the rough opening that were not insulated. Remove the interior casing and fill any gaps with low-expansion foam rated for windows and doors. Do not use standard expanding foam, which generates too much pressure and can bow the frame.
Sash hard to open or balance failure: The same sash mechanisms are used in new construction and replacement windows. Clean the tracks with a vacuum and apply dry silicone lubricant. For balance failures (sash drops when released), order a matching replacement balance from Lowe's based on sash weight and balance length.
Exterior condensation: Morning dew on the outside of the glass is normal and indicates the Low-E coating is insulating properly. This occurs most often in spring and fall when overnight temperatures drop quickly. It evaporates on its own and is not a sign of window failure.
Nailing fin damage: If the nailing fin is bent or cracked during framing or siding installation, the window's weather seal is compromised. Minor bends can be straightened carefully. Cracks in the fin should be sealed with flashing tape to maintain the water barrier. Severely damaged fins may require window replacement before siding is installed.
Maintenance Guide
Cleaning vinyl frames: Wash with mild soap and warm water. Avoid solvent-based cleaners, abrasive pads, or pressure washers aimed directly at the window seals. Clean twice a year at minimum. After construction is complete, remove any adhesive residue, stucco spatter, or paint overspray from the vinyl with a plastic scraper and rubbing alcohol, as these can stain if left on too long.
Lubricating tracks: Once the house is occupied, vacuum the sash tracks annually and apply dry silicone lubricant. During the construction phase, tracks can accumulate drywall dust, sawdust, and paint chips. Do a thorough deep clean of all tracks before final occupancy. This prevents premature wear on the weatherstripping and rollers.
Replacing weatherstripping: Weatherstripping on new construction windows is the same as on replacement windows. Over time, compression seals flatten and pile strips wear down. Replace with matching profiles from Lowe's. On new construction windows, also check the seal between the nailing fin and the exterior cladding each year, as settling can open small gaps.
Inspecting flashing and exterior seals: Once a year, examine the caulk joint where the exterior trim or siding meets the window frame. Look for cracks, gaps, or peeling caulk. Re-seal with exterior-grade polyurethane or silicone sealant. Also verify that the weep holes at the bottom of the frame are clear of debris so water can drain properly.
Post-construction cleanup: After construction or renovation work, clean all window tracks, sashes, and hardware thoroughly. Construction dust, drywall compound, and paint overspray can damage weatherstripping and jam moving parts if left in place. Remove protective film from glass and frames within 30 days of installation to prevent adhesive bonding.
Screen and hardware inspection: Check screens for damage from construction activity. Inspect sash locks, tilt latches, and balances annually. Tighten loose screws and apply dry silicone to pivot points and tracks. Addressing minor issues promptly prevents premature wear and maintains the factory seal performance.
Frequently Asked Questions
Can I use new construction windows in a remodel?
Yes, but only if you are removing the existing window frame down to the rough opening and re-doing the exterior cladding around the window. This is common in full renovations where siding is being replaced. If your existing frame is in good condition and you want to keep the siding intact, replacement windows are the simpler and less expensive choice.
Do RELIABILT new construction windows meet current building codes?
The 3500 Series meets or exceeds Energy Star requirements for all US climate zones, which satisfies the energy code in most jurisdictions. The 3201 Series meets code in northern and north-central zones. Always verify with your local building department, as some municipalities have requirements beyond the base energy code, such as impact ratings in hurricane zones.
How important is flashing for new construction windows?
Flashing is critical. It is the primary defense against water entering the wall cavity around the window. Even a high-quality window will leak if flashed incorrectly. Use self-adhesive flashing tape applied in shingle-fashion (bottom first, then sides, then head). Install a sill pan that slopes outward.
Follow the flashing tape manufacturer's instructions for integration with your house wrap or weather-resistive barrier. Many building inspectors will specifically check window flashing before approving the rough inspection.
If your existing window frames are in good shape, replacement windows are simpler and cheaper. New construction windows need exterior window casing and flashing. See the full RELIABILT window guide for series comparison.
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