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9th Edition Massachusetts Building Code

Published August 25, 2017 by Paul R. LaRochelle

Click here to download the Summary Changes PDF.

The residential building industry in Massachusetts is getting ready for a new set of changes in the Building Code. The final draft of the Ninth Edition is out and awaiting final public comments before adoption and enforcement begins. The concurrency period will end on January 1st, 2018.

In the meantime, the Eighth Edition of the Residential Building Code, which consists of the 2009 International Residential Code (IRC) with the Massachusetts Building Code (780 CMR) amendments, is in effect. The Ninth Edition will be based on the 2015 International Residential Code (IRC) with new amendments. The International Building Code (IBC) is the base code for all other building uses NOT relating to residential use, and its changes are beyond the scope of this article.

The Home Builders and Remodelers Association of Massachusetts has tabulated the changes and commented on cost effects expected from the IRC and the Massachusetts amendments. Here is a summary of what can be expected and how the new code might change the costs.

Proposed Residential Construction Cost Decreases

Lodging Houses (Bed and Breakfast) would be included in the residential code if they are owner occupied, three stories or less in height and limited to five guest rooms. These buildings would not have to comply with the more restrictive IBC code requirements, which would require sprinklers.

Protection Of Openings for high wind locations may no longer be required. This is due to the new definition of a Windborne Debris Areas within a hurricane-prone region, which is defined as region located in one of two parameters:

  1. Within 1 mile of the coastal mean high water line where the ultimate design wind speed, Vasd, is 130 mph or greater; OR
  2. In areas where the ultimate design wind speed, Vasd, is 140 mph or greater.

They would convert to Vult wind speeds of 170 mph and 180 mph, which do not occur in Massachusetts.

Wind Limitation And Wind Design required by codes other than the IRC in high wind areas was previously applicable to 49 municipalities; this would be reduced to 19 municipalities in the Ninth edition.

Seismic Provisions would be suspended for limited size residential buildings due to seismic re-mapping. This means that townhouses would be exempt from meeting the seismic provisions per Massachusetts-unique amendment.

Sprinklers For Townhouses would not be required, provided that the common walls dividing the units have a 2 hour fire resistance rating. One hour fire resistant wall construction would still require a sprinkler system. 

Townhouses Would Be Entirely Covered In the Residential Code. Currently, the IBC is used to govern fire protection, wind, and seismic design and the IRC is used to govern egress and other design requirements. 

Work Exempt From Permit would now apply to fences less than 7 feet instead of 6 feet.

Fire Protection Of Floors: penetrations or openings for ducts, vents, electrical outlets, lighting, devices, luminaires, wires speakers, drainage, piping and similar openings or penetrations would no longer be regulated.

Minimum Area For A Habitable Room would be reduced from 120 square feet to 70 square feet. Smaller bedrooms would now be allowable.

Glazing In Hazardous Locations would be governed by seven separate sections, which would allow for greater design flexibility. For example, the threshold for the minimum height of safety glazing required above the walking surface would be reduced to 36 inches instead of 60 inches currently required.

Landings For Stairways would be allowed to be designed in shapes other than square or rectangular, such as angular or curved.

A Portal Frame With Hold-Downs would be reduced from the required capacity of 4,200 pounds to 3,500 pounds for the two straps.

Wall Bracing would be simplified with the addition of a new section which provides for a simplified method that is an easy, prescriptive procedure.

Header Design would be revised to allow single 2x lumber headers and rim board trim headers. There would be new size and load tables for open porch headers and full height studs at each end of the headers.

Roof Tie Down Design Improvements would help with the roof uplift provisions. Under specific limitations, the requirements for manufactured metal straps would be allowed to be replaced with nailing.

Roof Ventilation Minimum Area would be redefined. The exception for reducing the ventilation area when a vapor retarder is installed on the ceiling would only apply to cold weather climates. The requirement for the upper vents to be installed at least 3 feet above the eave vents would be removed.

R-Value Computation Method would allow insulated siding to be used in the calculation for satisfying the wall insulation value.

Access Hatches And Vertical Doors would not have to match the R-value (the required wall insulation value) when accessing an unconditioned attic or crawl space, but would have to meet the fenestration U-factor requirements.

Stretch Code would be simplified and would not apply to existing buildings at all.

Proposed Residential Construction Cost Increases

Action On Permit Application would be required to be taken in 30 calendar days, not business days. This is presently not clear in the Massachusetts amendments.

Opening Protection safety requirement would mandate self-closing devices to be installed for doors between garage and dwelling unit in order to prevent poisonous gases from entering the house. Doors would have to be solid wood doors not less than 1 3/8 inches thick or honeycomb core steel doors not less than 1-3/8 inches thick. Openings from garage into a sleeping area would not be permitted.

Safety Glazing would be required in areas near indoor and outdoor swimming pools.

Window Wells would be required to be designed for proper drainage and to be connected into the building's foundation drain system or by an approved alternative method. Window wells serving emergency escape and rescue openings would be required to be designed to direct surface water to the foundation drainage system.

Flood Construction In Coastal A Zones would have more stringent requirements, almost as restrictive as the V zone requirements.

Flood Construction In A/AO Zones: the elevation would be raised one foot above the previous level.

Footings would have a mandated minimum size depending on the snow load, soil type and building type of construction. Soils with a low bearing value and supporting brick veneer or masonry would have larger footing requirements.

Foundation Anchorage would be required to be placed in the middle third of the width of the sill plate.

Energy Efficiency Conservation Measures would require a lower HERS rating for new construction; one or more electric vehicle 40 amp wired circuits for electric vehicle charging; certified testers for whole house or duct air leakage and a more energy efficient fenestration (U factor lowered from 0.32 to 0.30).

Air Barrier And Insulation Installation would be necessary in cavities within corners and headers and could be accomplished by completely filling the cavity with material having a thermal resistance of R3 per inch of thickness.

Smoke, Heat And Carbon Monoxide Detectors would be required to be installed throughout the entire existing dwelling if a dwelling or townhouse undergoes reconstruction such that more than 50% of both walls and ceilings are opened to framing.

A Solar Ready Zone would be required on the roof for new residential construction. The area would have to be no less than 300 square feet in size, exclusive of mandatory setbacks as required by the International Fire Code.

This is an overview of the changes and cost implications which are anticipated to occur with the adoption of the Ninth Edition of the Residential Building Code. Please note there are additional changes proposed, ones that are more cost neutral but are of consequence to the design and construction. 

Get in touch!

Please contact Coastal Engineering Co., Inc. for a full review or with any specific questions you may have.