Interior and Exterior Door Installation
Door installation includes fitting the unit to the opening, aligning the swing and latch, and coordinating the casing and hardware. LM Legacy Remodeling installs interior and exterior doors throughout Delaware County and the Main Line, including prehung units, replacement slabs, closet doors, casing, and hardware.
The jamb, sill, wall thickness, floor height, existing trim, and opening are inspected before the installation method is selected. Those conditions determine whether the project requires a complete prehung assembly or whether a new slab can be fitted to the existing jamb.
Prehung Doors vs. Replacement Slabs
A prehung door includes the door, jamb, and hinges as one assembly. It is normally the better choice when the existing jamb is damaged, out of square, poorly weather-sealed, or being replaced as part of a larger trim update.
A replacement slab is fitted to the jamb already in place. This can be less invasive when the existing jamb is solid and correctly positioned, but the new door still has to be sized, mortised, beveled where needed, and aligned to the existing strike and hinges.
Exterior entry door replacement — LM Legacy Remodeling
Door Services We Offer
- Interior Prehung Doors — Complete door-and-jamb replacements set plumb with even reveals.
- Interior Slab Replacements — New slabs fitted to sound existing jambs, including hinge and latch preparation.
- Exterior Entry Doors — Replacement entry units with sill, weather sealing, casing, and hardware coordinated to the opening.
- Closet Doors — Bifold, bypass, and swinging closet doors, including new track or hinge hardware.
- Door Casing — New casing, back band, plinth blocks, and transitions to existing baseboard.
- Door Hardware — Knobs, levers, hinges, latches, and strike plates installed and adjusted as part of the agreed scope.
Exterior Door Fit and Weather Sealing
Exterior door replacement involves more than fastening a new unit into the opening. The sill must be supported, the frame must be set square, and the perimeter must be sealed to limit drafts and water intrusion. Existing rot, damaged framing, masonry conditions, or unusual wall thickness can affect the installation and are reviewed before the final scope is written.
Door Casing and Trim
Door casing should connect cleanly with the baseboard and match the proportions of the surrounding room. We can replace casing with the door or retain existing trim when its condition and dimensions allow it. Where the new jamb depth differs from the wall, extension material is fitted before casing is installed.
Factors That Affect the Installation Scope
- Door type — Slab, prehung, bifold, bypass, and exterior entry units require different preparation and installation methods.
- Opening condition — Out-of-square framing, damaged jambs, rot, and uneven floors may require additional fitting or repair.
- Casing and finish trim — The scope identifies whether sound casing remains or a complete new trim package is installed.
- Hardware — Hinges, locksets, deadbolts, and specialty hardware have different preparation requirements.
- Finish responsibilities — Painting, staining, caulking, and touch-up responsibilities are identified in writing.
Each opening is measured so the door type, handing, trim, hardware, preparation, and finish responsibilities can be documented in the written scope.
Frequently Asked Questions — Interior and Exterior Door Installation
Do I need a prehung door or just a new slab?
A prehung unit is usually the better choice when the existing jamb is damaged, out of square, poorly sealed, or being replaced with the surrounding trim. A slab can be fitted to a sound existing jamb when its size and position work with the new door. The opening is inspected before the installation method and scope are finalized.
Can an exterior door be replaced without changing the size of the opening?
Often, yes. A replacement unit can usually be ordered for the existing rough opening, but the sill, wall thickness, trim, and framing condition still have to be checked. If the opening needs structural alteration or hidden repair, that work is identified separately.
Can I purchase the door myself?
Yes, when the selected door is correctly sized and suited to the opening. We recommend confirming the measurements, handing, swing, jamb depth, and exterior exposure before ordering. The written estimate will state who supplies the door and hardware.
Does door installation include casing and hardware?
It can. Casing, hinges, knobs, levers, deadbolts, and strike plates are included or excluded according to the written scope. We do not assume every opening needs the same package.
Do you paint or stain the new door?
Painting or staining is handled according to the project scope. The estimate identifies whether the door and trim will be left ready for a painter or whether finish work is included.
Our Process
- Opening inspection — We measure the opening and check the jamb, sill, floor, wall thickness, and surrounding trim.
- Door and hardware selection — We confirm the door style, handing, swing, casing, hinges, and lockset before material is ordered.
- Clear written scope — The estimate identifies each opening and whether it receives a slab, prehung unit, casing, hardware, and finish work.
- Installation and adjustment — The assembly is set, fitted, fastened, and adjusted for an even reveal, smooth swing, and reliable latch.
- Finish preparation and walkthrough — Included holes and joints are prepared, the work area is cleaned, and each door is operated during the final review.
Areas We Serve
We work throughout Delaware County, the Main Line, and selected communities in Chester and Montgomery Counties. We also provide finish carpentry in Chester and Montgomery Counties for homeowners throughout the western Philadelphia suburbs.