How to Visualize an Attic Conversion Before You Build It

An attic is the one addition that's already there — the floor exists, the roof is already overhead, and the project is finishing a space rather than building a new one. It's also the addition where the gap between "this looks big enough" and "this is legally habitable space" is the widest: headroom, a dormer, and a real staircase can all be non-negotiable before the square footage counts for anything. Here's how to see both the outside and the inside from one set of photos in a few minutes, and exactly where the result stops being something you can build from.

Step 1: Shoot the roofline outside, then the attic itself

• Photograph the roof elevation where a dormer would go — straight-on if you can, so the tool reads the existing roof pitch, ridge line, and siding it has to tie a new dormer into.
• Get enough of the roofline on either side of the proposed dormer in frame for it to read as built into the roof, not floating above it.
• Photograph the inside with the rafters and the floor visible and as empty as it is now — clutter and stored boxes in frame can get redrawn into something else rather than simply removed.
• A phone photo is enough for both shots — no site plan or survey needed to start.

Step 2: Add the dormer or window on the outside

Upload the roof photo to Exterior AI and write the prompt as the specific change: "add a shed dormer centered on this roof slope, matching the existing siding and trim, two double-hung windows, roofing shingles matching the rest of the roof." Leave Structure Lock off here — it defaults off on Exterior AI specifically because adding a dormer is a change to the massing, not just the materials. Each run is 100 credits.

Step 3: Finish the inside as the room it's becoming

Upload the interior shot to Interior AI and pick the closest room type to what the attic is becoming — Bedroom, Kids Bedroom, Home Office, and Home Gym are all in the 22-option dropdown — or write your own room description if none of them fit. Describe the finish directly: "drywall and paint between the rafters, engineered wood flooring over the subfloor, a window seat built into the dormer, recessed lighting along the ridge." Leave Structure Lock off, since turning a raw attic into a finished room is exactly the kind of change it's designed to allow. Each run is 100 credits.

Step 4: Working from a sketch instead

If you've already sketched the new roofline — where the dormer sits, how wide it runs, where the headroom clears — run that sketch through Sketch to Image with Structure Lock on. It's designed to hold the lines you drew rather than reinterpret them, which matters once you've settled on a dormer's size and position and don't want the tool proposing its own.

Step 5: Compare directions before anyone opens the roof

At 100–100 credits a run, it's cheaper to compare a shed dormer against a gable dormer, or an office layout against a bedroom one, than to open the roof and decide you wanted something else. Run the exterior and interior separately — each one is a smaller, more specific change for the tool to make than one prompt trying to do both.

Where this is not enough

An attic conversion is one of the more code-heavy small renovations precisely because the space was never built to be lived in — be clear about what the image is before anyone relies on it for a decision that costs money.

• It's a presentation visual, not a permit or structural drawing. Most building codes — including the International Residential Code — require a minimum ceiling height over a set share of the room's floor area before the space counts as habitable, and a sloped attic ceiling can fall short of it without a dormer to raise the roofline where it matters. The render can show any headroom you ask for; it doesn't check whether your actual rafters clear it.
• Attic floor joists are usually sized to carry stored boxes, not a bedroom's worth of furniture and foot traffic. Whether the existing framing can take a habitable live load — or needs to be reinforced — is a question for a licensed structural engineer, not the image.
• A pull-down ladder doesn't count as access. Most codes require a fixed, code-compliant staircase to any room used as a bedroom or regular living space, and that staircase has to come from somewhere in the floor plan below — a decision the render doesn't make for you.
• If the room is meant to be a bedroom, it typically needs an egress window sized and placed to a code minimum, not just a window. Where that opening falls limits where a dormer actually has to go.
• It redraws the whole frame, including what you didn't mention — expect the roof texture, the gutter line, or the trim below the eave to shift slightly even when the prompt only asked for the dormer. Compare the result against the original before you call it final.
• For a measured, exportable 3D model of the finished space — one you can section, dimension, and hand to a contractor for pricing — model it in Design Studio instead, included with every account.