Screen Room to Three-Season Sunroom Conversion in Atkinson, NH (Before & After)

Every town in southern New Hampshire has them: screened porches built in the 80s and 90s that started out great and slowly became the least-used room in the house. Wood framing goes gray, screens sag, leaves blow in all fall, and by mid-September the space is basically storage. That is exactly what we walked into on this Atkinson, NH project, and what we handed back was a bright three-season sunroom the homeowners now use from early spring through late fall.

Key Takeaways

• •Project: existing screened porch in Atkinson, NH converted into a finished three-season sunroom.
• •Scope: new window wall, insulated exterior walls, gray vinyl siding with white trim, pine plank ceiling, beadboard wainscot, and a rebuilt composite stair and railing.
• •Three-season means comfortable roughly April through November without a full heating and cooling tie-in, which keeps cost and permitting far simpler than a four-season addition.
• •Typical installed cost for a comparable screen room to three-season sunroom conversion in Rockingham County runs about $28,000 to $55,000.
• •We build the same conversions in Plaistow, Hampstead, Salem, Windham, Danville, Newton, Kingston, Sandown, and Derry, NH, plus Haverhill and Methuen, MA.

What We Started With

The original porch was structurally sound underneath but cosmetically finished. The framing had weathered to a flat gray, the screen panels had stretched and torn at the staples, and the stair to the yard had softened at the stringers. The homeowners told us the space was pleasant for about eight weeks a year and unusable the rest of the time. They did not want a full four-season addition with heat, cooling, and the insulation and permitting that comes with it. They wanted a real, finished room they could open up in April and enjoy through Thanksgiving.

Three-Season vs. Four-Season: Why We Recommended Three

A four-season sunroom is a conditioned addition. It needs full insulation in walls, floor, and roof, an HVAC tie-in or dedicated mini-split, and it gets reviewed as living space, which raises both the build cost and the assessed value of the home. A three-season sunroom is finished and weathertight, closed in with real windows and siding, but it is not intended to be heated through a New Hampshire January. For this family, the three-season route delivered roughly 90 percent of the usable enjoyment at a substantially lower cost, and it kept the project on a much shorter schedule.

One thing we always tell homeowners in Atkinson and the surrounding towns: build the three-season room so it can be upgraded later. We frame and detail these conversions so that adding insulation and a mini-split down the road is a straightforward project rather than a tear-apart.

The Build: Enclosing the Porch

We stripped the screen panels and old trim down to the frame, verified the posts, beam, and deck structure, and sistered what needed reinforcement. From there we framed real window openings, set a wraparound run of white-trimmed windows to keep the open, airy feel the screened porch always had, and sheathed and wrapped the knee walls. The exterior got new gray vinyl siding with crisp white corner boards and trim so the room reads as part of the original house rather than a bolt-on.

Inside: Pine Ceiling, Beadboard, and Light

The interior is where this one really earns its keep. We ran a natural pine plank ceiling for warmth and texture, wrapped the lower walls in painted beadboard wainscot, and let the window wall do the rest. Because the room faces the yard, morning light fills the whole space, and the pine keeps it from ever feeling cold or clinical. The floor and trim were detailed to match the adjacent interior of the house so it feels like a room, not a porch with windows.

The New Stair and Railing

The old stair came out entirely. We rebuilt it with pressure-treated framing, composite treads, and a white composite railing that ties into the trim package on the room. Composite on stairs is worth every dollar in New Hampshire: stair treads take the worst of the freeze-thaw cycle, the ice melt, and the shovel, and they are the first thing to rot on a wood-built porch.

What a Conversion Like This Costs in Southern NH

For a comparable screen room to three-season sunroom conversion in Atkinson and the surrounding Rockingham County towns, installed pricing typically lands between $28,000 and $55,000. The spread comes down to the size of the room, how much of the existing structure can be reused, the window package you choose, whether the roof needs to be re-tied or re-shingled, and the interior finish level. A four-season conversion with insulation and a mini-split generally adds $12,000 to $25,000 on top of that.

Permits and Timeline

Enclosing an existing porch is a permitted project in Atkinson. We pull the building permit through the Atkinson Building Department, and because we are reusing an existing footprint and foundation, the review is usually straightforward compared to a new addition. Most conversions of this size run three to five weeks on site once materials are staged, and we sequence the work so the house stays sealed and secure the entire time.

Thinking About Your Own Porch?

If you have a screened porch that only earns its keep for two months a year, a three-season conversion is one of the highest-value projects you can do to a home in southern New Hampshire. We are a licensed, insured, veteran-owned general contractor based in Plaistow, minutes from Atkinson, and estimates are free. Call 603-797-9224 or request an estimate online and we will walk the space with you.