Lot & site types

Understanding your lot before you choose a plan

The shape of the lot decides which plan fits. The hazards on the lot decide whether the set can be unstamped or needs a licensed review. Here is how we handle each one.

Setback, height and coverage numbers below are typical examples, not your town's rules. Your zoning code and your building official decide; we read the published rules for you in the feasibility report and you confirm them with the town.

Lot shapes

Which plan fits

Standard lot

The rectangular suburban lot

The challenge

Most suburban lots in Massachusetts are 50 to 100 ft wide and 100 to 200 ft deep with the house near the front. The question is usually rear-yard room: rear and side setbacks for accessory buildings (often 5 to 10 ft, sometimes more for a dwelling), lot coverage, and the distance from the main house.

How we handle it

Every plan page states the footprint and ridge height so you can check it against your setbacks and height limit. The site-adapted set places the building on a site plan drawn from your survey or certified plot plan, with the setbacks dimensioned for the reviewer.

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Narrow lot

Under 50 ft wide

The challenge

With 5 ft side setbacks a 40 ft lot leaves 30 ft of buildable width, and a driveway past the house eats more. Older neighbourhoods in Worcester, Lowell and Somerville are full of these lots.

How we handle it

The catalog's 12, 16 and 20 ft wide plans are drawn for exactly this: a one-car garage (The Tack Room), a 12 x 16 or 16 x 20 workshop, the 16 x 24 studio cottage (The Wren) and the 20 x 20 studio (The Finch). Filter the catalog by building width.

Plans 10 to 20 ft wide

Corner lot

Two street frontages

The challenge

Many towns apply a front setback to both streets, and some restrict accessory buildings to the rear yard as measured from the primary frontage. That can shrink the buildable area and change which way a garage door can face.

How we handle it

Our garages are front-gable, so the door wall is a gable end and the plan can be mirrored or rotated on the site plan without changing the structure. The feasibility report reads the corner-lot clause in your zoning code before you pick a plan.

Garage plans

Alley lot

Rear access from a lane

The challenge

An alley gives the garage its own driveway, which is the classic garage-apartment arrangement. Towns often allow a smaller rear setback from an alley but may require the door to be set back far enough for a car to turn in.

How we handle it

The Osprey (28 x 24) and The Eagle (30 x 26) put a two-car garage on the alley and a one-bedroom apartment above, with an interior stair. In Massachusetts the apartment counts toward the 900 sq ft by-right ADU limit; the garage below does not.

Garage apartment plans

Sloped lot

Grade that falls across the footprint

The challenge

A slab on grade wants a level pad. Mild slopes are handled with stepped footings and a little cut and fill; steep slopes need retaining walls, walk-out foundations or engineered solutions.

How we handle it

Up to about 15 percent across the footprint the code's stepped-footing rules apply and the set stays prescriptive, with the steps shown on the foundation plan. Steeper than that, or any retaining wall taller than the code's prescriptive limit, goes to the licensed-review lane. Tell us the slope at intake; if you do not know it, say so and we will estimate from public mapping and flag it.

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Sites that need a licensed review

Outside the code's prescriptive limits

The residential code's tables stop at certain wind speeds, snow loads, seismic categories and soil conditions. Beyond them the code itself calls for engineered design, and these sets are reviewed and sealed by an independent engineer or architect licensed in your state, under a separate agreement with you, at added cost. Flood-zone lots always go to licensed review.

Licensed review

High wind

The challenge

The catalog envelope is 130 mph ultimate design wind speed. Cape Cod and the Islands (up to 137 mph in the state's town table), coastal sites with open-water exposure, and any wind-borne-debris region push past the tables' assumptions on exposure, uplift and opening protection.

How we handle it

The gate reads your town's published wind speed and exposure. Over the limit, the set is prepared for the licensed partner, who checks uplift, connections and shear and seals the set.

Licensed review

High seismic

The challenge

Seismic design categories D and E add bracing, anchorage and irregularity rules that the standard tables do not cover for every layout. Almost all of the Northeast is category A, B or C, which is why the envelope stops at C.

How we handle it

The gate checks the mapped category for your site. Category D or E, or an irregular shape in D, goes to the licensed partner. If your town publishes a different category than the maps, the town's value wins.

Licensed review

Heavy snow

The challenge

The rafter and ceiling-joist tables run to 70 psf ground snow; our catalog envelope is 50 psf. Massachusetts' town table runs from 25 psf on the Cape to 60 psf in the Berkshires and the northern Worcester County hills; sites above 50 psf get the plan re-run for the town.

How we handle it

Between 50 and 70 psf the site-adapted set re-sizes the roof from the tables and stays prescriptive. Above 70 psf, or where the town requires engineered roof design, the set goes to the licensed partner.

Licensed review

Flood zone

The challenge

FEMA special flood hazard areas (zones A and V) bring elevation, flood-resistant materials, flood openings and often certified elevation data. Habitable space has to sit above the design flood elevation.

How we handle it

Intake asks for the FEMA map panel and we help you look it up. In Massachusetts any flood-zone lot needs sealed documents (780 CMR R322), so it goes to the licensed partner; we will tell you and refund you if we learn it after payment.

Licensed review

Poor or unknown soil

The challenge

Fill, organic or wet soils, expansive clay, ledge at the surface or a high water table change the footing design. The prescriptive footing tables assume a sound bearing soil.

How we handle it

With no soil report we design to the conservative 1,500 psf presumptive value the code allows and flag it on the foundation plan for the inspector to confirm at the footing excavation. Known fill, organic soil, expansive clay or a high water table at footing depth goes to the licensed partner, who may ask for a soils report.

Start here: the free checklist

Lot facts, zoning questions for your town, and the site hazards that decide the lane, on one printable page.

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