As a planning range at the national average, a Standard sunroom centres on $187 per square foot for structure, before foundation and features. A 200 sq ft room therefore centres on about $37,400, and a 300 sq ft room on about $56,100, before those extras.

Yes, usually. The lighter insulation, glazing, and heating specification of a three-season room costs less to build, but it also limits when the room is comfortable. Compare like with like, and decide on use before comparing prices.

It needs proper support and a level base matched to the existing house. Whether that is a slab, piers, or another foundation depends on the ground, the design, and local requirements — ask the builder to specify it in the bid.

A well-built, well-insulated sunroom that fits the house usually helps, but the return depends on the local market and on whether the room is genuinely usable year-round. Treat any resale figure as an estimate, not a guarantee.

As a broad planning guide, a small prefabricated room without plumbing is often in the $20,000–$35,000 range, a mid-size addition in the $35,000–$70,000 range, and a large or plumbed addition at $70,000–$120,000 or more, including on-site work. The site portion moves the total considerably.

It can be, often by roughly 10–20% on a comparable scope, and it is usually faster. The saving depends on the site, the module, and the on-site work, so compare full totals, not module prices alone.

Factory work runs while the site is prepared, so the on-site period is shorter than a conventional build. Delivery, crane, connections, and finishing still need a realistic programme.

Tight access, difficult crane positions, steep or restricted sites, and very complex shapes can erase the advantage. Check access and lifting early.

As a planning guide, a compact full bathroom with a shower is often around 35–40 square feet at the tight end, and 45–55 square feet is more comfortable. Shower, toilet, and basin clearances decide usability more than total area.

About 32 by 32 inches is a tight minimum, and 36 by 36 inches is noticeably more comfortable. A walk-in shower needs more floor area and careful drainage.

A compact bath can fit, but it usually leaves less room for movement and storage than a shower in the same footprint. A shower usually suits a small room better.

Not always. Plumbing, waterproofing, tiling, and fixtures matter more than size alone, so a small premium bathroom can cost as much as a larger standard one.

As a planning figure, a 400 sq ft Standard room addition on a slab centres on $66,000 in Texas, with a range of $59,400–$79,200. Your size, finish, foundation, and features move the figure more than the state average does.

Two contractors rarely price the same plans identically, and material prices move. The range runs 10% below to 20% above the central figure.

Design and permit fees, site surprises such as rock or poor soil, landscaping, and furniture are not itemised. Keep a contingency for them.

Run the calculator with your size, finish, foundation, features, and Texas selected, or see the Texas state page for the full table.

As a planning figure, a 400 sq ft Standard room addition on a slab centres on $59,400 in South Carolina, with a range of $53,460–$71,280. Your size, finish, foundation, and features move the figure more than the state average does.

Two contractors rarely price the same plans identically, and material prices move. The range runs 10% below to 20% above the central figure.

Design and permit fees, site surprises such as rock or poor soil, landscaping, and furniture are not itemised. Keep a contingency for them.

Run the calculator with your size, finish, foundation, features, and South Carolina selected, or see the South Carolina state page for the full table.

As a planning figure, a 400 sq ft Standard room addition on a slab centres on $73,920 in Colorado, with a range of $66,528–$88,704. Your size, finish, foundation, and features move the figure more than the state average does.

Two contractors rarely price the same plans identically, and material prices move. The range runs 10% below to 20% above the central figure.

Design and permit fees, site surprises such as rock or poor soil, landscaping, and furniture are not itemised. Keep a contingency for them.

Run the calculator with your size, finish, foundation, features, and Colorado selected, or see the Colorado state page for the full table.

As a planning figure, a 400 sq ft Standard room addition on a slab centres on $100,980 in California, with a range of $90,882–$121,176. Your size, finish, foundation, and features move the figure more than the state average does.

Two contractors rarely price the same plans identically, and material prices move. The range runs 10% below to 20% above the central figure.

Design and permit fees, site surprises such as rock or poor soil, landscaping, and furniture are not itemised. Keep a contingency for them.

Run the calculator with your size, finish, foundation, features, and California selected, or see the California state page for the full table.

It depends on the end use. A simple room conversion costs materially less than a full ADU-level conversion, which at 400 sq ft and a Standard rate centres on about $100,000 in the ADU calculator. Use the calculator with your size, finish, and features for a planning figure.

It depends on the area and the buyer. A well-done extra bedroom or suite often helps, but losing covered parking and storage can offset part of the gain. Think about both sides before deciding.

Yes, and it is common in suite conversions. Plumbing distance and drainage decide much of the extra cost, so check them early.

Usually making an uninsulated, damp-prone shell into a warm, dry, well-lit living space — insulation, floor, headroom, and services, not the finishes.

As a planning range at the national average, a Standard bathroom centres on $300 per square foot for structure, before fixtures and features. A 50 sq ft half bathroom centres on about $15,000 and an 80 sq ft full bathroom on about $24,000 on that basis, before the plumbing run and fixtures.

Usually yes, because there is less plumbing, drainage, and wet-area work. The gap depends on the plumbing distance and the fixture specification, so compare itemised bids rather than headline totals.

Usually next to, or directly above, existing plumbing, where soil and water runs are short and the existing system has capacity. A far corner of the house is usually the most expensive place.

An extra bathroom usually helps a home that is short of bathrooms, especially a well-placed second bathroom. The return depends on the local market and the quality of the work, so treat it as an estimate, not a guarantee.

At the national average on a slab with no optional features, a 500 sq ft room addition centres on $52,500 at Economy, $82,500 at Standard, and $137,500 at Premium. Kitchen, second-story, and sunroom figures are higher, as the table shows.

Yes — it is two rooms, a large living space, or a suite. The layout and split of uses matter as much as the total area.

Finish level first, then addition type, then a bathroom, basement foundation, or complex roof tie-in. Test each one in the calculator.

Design and permit fees, site surprises, landscaping, and furniture are not itemised. Keep a contingency for them.