Radon resistant construction

A requirement of the new Maine Uniform Building and Energy Code (MUBEC) is Radon resistant construction techniques.


Radon, a soil gas that is prevalent throughout Maine has been linked to lung cancer.



We have previously partnered with the EPA to incorporate Radon resistant construction techniques in all new construction and believe that including it in the new building code was the right thing to do.


Many of the techniques were already included in our standard specifications, so it was fairly simple and inexpensive to comply with the remaining requirements and made sense to do so even before it became required by code.



An overview of the techniques follows:

• Utilize perforated pipe for drainage/venting below basement concrete floor





• Back fill below basement concrete floor with clean gravel or crushed stone
  




• Utilize a poly vapor barrier above the gravel/stone and beneath basement concrete floor sealing the edges and penetrations with silicon caulk. Seal any foundation penetrations or cracks with silicon caulk





• Connect a PVC vent pipe to the below slab drain/vent piping and run vertically within the building enclosure and through the roof deck to vent soil gasses





• Add an electric outlet location in the attic space for a future vent fan if ever required

Together with appropriate building enclosure ventilation practices, these construction techniques will help assure homeowners of a healthy home living environment.

New Energy Codes in Maine

In an effort to achieve conformity throughout the state, Maine has adopted the "Maine Uniform Building and Energy Code".

These new codes are now in effect in many cities and towns, and will be enacted statewide by July 1, 2012.

We welcome these new codes. We have always had a strong focus on energy efficiency and have typically exceeded code in an effort to achieve tight, well insulated houses that are easy to heat.

Some of the required changes however will add cost to a building project. As an example, foundation walls will now require continuous R-15 insulation, and concrete floors will require R-1o.

There are minimum U-Factor requirements for windows and skylights as well.

The following summary details the requirements by building enclosure element for Maine zone 6 ( all of Maine is zone 6 except Aroostook county which is zone 7).

Fenestration U-Factor: 0.35

Skylight U-Factor: 0.60

Ceiling R-Value: 49

Wood Frame Wall R-Value: 20 or 13+5(R-13 cavity insulation plus R-5 insulated sheathing)

Mass Wall R-Value: 15/19 (the second R-Value applies when more than half of the insulation is on the interior of the mass wall)

Floor R-Value: 30

Basement Wall R-Value: 15/19(R-15 continuous insulation on the interior or exterior, or R-19 cavity insulation on the interior)

Slab R-Value and Depth: 10, 4ft

Crawl Space Wall R-Value: 10/13

There are a number of strategies to achieve these new requirements. If you have questions about how these changes might effect your future project and which solutions will best balance performance and cost please contact me as I look forward to speaking with you further.

"Advanced Building Materials"

As advancements are made in building material development, quality home builders must continue to remain educated regarding construction methods and techniques that work in synergy with these advanced materials to eliminate potential future problems.
An excellent article by Building Science Corporation explores this topic in detail and can be found at the following link:http://www.buildingscience.com/documents/insights/bsi-039-five-things?topic=doctypes/insights

"Winkumpaugh Cottage"

Moisture Management

Building science case studies are educating Maine home builders on the importance of properly managing moisture in new building construction.

It is unsettling that practices which were considered acceptable for many years are now being questioned as ineffective and even potentially damaging regarding proper moisture management.

Our goals for moisture management are:

• To prohibit bulk moisture from entering the building envelope from the exterior by effectively weather sealing the structure




• To regulate how moisture vapor on the interior of the building enters wall assemblies




• To provide an opportunity for any moisture within the wall assembly to be able to dry to either the exterior or the interior
  
  

Best industry practices should always be utilized for weather sealing to prohibit bulk moisture from entering the structure.

This includes proper installation of roofing materials and flashing detail, weather barrier wrap installation and sealing, window and door installation, and exterior cladding installation and detail.

The following photographs detail proper window installation.

Wall systems should be designed so that moisture vapor within the conditioned space is regulated from entering the assembly, yet able to dry either to the exterior or to the interior if it does enter an assembly.

The first strategy to keep moisture vapor from entering the structure is extensive air sealing all gaps, joints and seams in the frame as air movement from conditioned to unconditioned space is the principal cause of moisture entering insulated assemblies.

A few cans of DOW Professional foam and a little time effectively seals all sheathing seams, plate joints, window and door perimeters and mechanical system penetrations.

Our current project, "Winkumpaugh Cottage" utilizes DOW "SIS" structural insulated sheathing which has a perm rating of 0.03 (twice as impermeable as 6 mil poly). This requires that wall systems be allowed to dry to the inside of the structure as it is nearly impossible that any moisture could dry through the sheathing to the exterior.

But how can we prevent moisture vapor inside the structure from entering the wall system while at the same time allowing moisture vapor to dry to the interior? By installing a vapor retarder.

Building science case studies have determined proper vapor barrier/vapor retarder recommendations for all climate zones based upon average heating degree days and projected dew points within wall assemblies built to a variety of specifications.

In our climate zone, and with foam sheathed walls (the DOW SIS sheathing is continuous foam sheathing of R-5.5) it is recommended that a class III vapor barrier be utilized (class III requires permiance of less than 1.0 perm and greater than 0.1 perm).

An excellent choice to accomplish these parameters is Sherwin Williams Vapor Barrier Primer. It is a latex based product and applied as recommended has a perm rating of 0.9.

By any standard, this type of construction is both energy efficient and "tight", so measures must be taken to ensure ongoing indoor air quality that is both healthy for the occupants as well as for the structure.

We have specified Panasonic's "Whisper Comfort ERV (energy recovery ventilator)" for this project. In place of a typical bath fan, each unit will provide a continuous air exchange for up to 500 sq ft and is 66% efficient at capturing the heat from the stale air being expelled from the structure.

The near silent continuous operation (manual operation is also an option) consumes only 20 watts of electricity (less than most compact fluorescent light bulbs).

While construction techniques that produce sustainable, energy efficient structures that are healthy to live in may cost a little more than the construction practices which have been prevalent for several decades, we believe they are well worth the difference.

Would you be willing to pay more for a new home that is built to higher standards?

I look forward to hearing from you.

Insulation

Insulation that balances performance and cost

Unpredictable energy costs have made concerned Maine home builders seek better performing insulation alternatives to the traditional fiberglass batt insulation which had been prevalent for many years.

We feel an option that balances cost and performance very well is the "OPTIMA" blown in blanket system.

Manufactured by CertainTeed and installed locally by R.L. Garside Insulation Contractor, "OPTIMA" is a specially manufactured fiberglass designed for closed cavity installation.

The crew from Garside arrived at our site Wednesday morning and proceeded to install a speciality fabric enclosing all wall stud and roof rafter bays.

By mid day this was completed and installation of the fiberglass material started.

Bundles of "OPTIMA" insulation are placed into a machine on their truck that separates the compressed material and sends it on demand through a hose to the installer in the house who is directing the flow of materials into each wall cavity filling it completely.

An advantage of this system is that it fills wall cavities, regardless of shape, completely with no gaps or voids which is almost impossible to achieve with batt insulation.

The installed material has a greater density as well. Subsequently, R values are higher with "OPTIMA"( R-23 for 2x6 walls as compared to R-19 for fiberglass batts).

One crew from Garside returned the following morning to complete the installation. By noon the job was completed, everything was clean, and they were on their way to another job.

Together with the DOW "SIS" insulated sheathing, Winkumpaugh Cottage has walls which are R-28.5.

The roof system at Winkumpaugh Cottage includes "OPTIMA" filled 2x10 rafter cavities (R-40) and 1/2" DOW TUFF R rigid insulation with a 3/4" sealed airspace between the foil faced rigid insulation and the drywall ceiling (R-6.1) for a total R value of R-46.

Here is a review of our strategy to achieve excellent energy efficiency while at the same time controlling construction costs:

• OVE (optimum value engineered) framing techniques utilized to reduce framing material therefore creating space for additional insulation.




• Insulated sheathing utilized to create a continuous thermal break between wall framing and unconditioned space.
  
  


• Extensive wall sealing techniques employed to minimize air infiltration into the building envelope.
  
  


• Superior insulation utilized and installed following Energy Star thermal bypass guidelines to ensure insulation is in full contact with all (6) sides of each wall cavity.
  
  

Our next topic to be discussed will review moisture management and indoor air quality.

More at: http://www.gregfitzpatrickgc.com/

Wall sealing

Building science case studies have shown Maine home builders the importance of sealing wall systems to prevent air infiltration into the building envelope.

Reducing air infiltration is as important as adding additional insulation as a strategy for improving energy performance.

Additionally, leaky wall assemblies can be prone to condensation and water damage (mildew, mold, dry rot) as the air exchange creates cold spots for moisture laden air from within the building to condensate.

We have previously discussed measures we have taken to reduce thermal transfer and maximize space for insulation.

At this point framing is complete, roofing installed, windows and doors installed and we are tight to weather.

Soon the insulation and then drywall will be installed closing in the wall cavities. Prior to that occurring we have full access to the inside of the wall cavities and an opportunity to seal any areas that could potentially allow unconditioned air from outside the house to enter into the conditioned space of the building envelope.

Areas of concern are: the sill plate to concrete floor connection (even though we utilized sill seal foam during construction), all sheathing panel edges and perimeter openings for windows and doors(even though we taped all seams from the exterior with DOW Weathermate tape), and wall plate seams and penetrations.

DOW professional expanding foam sealant is utilized extensively in these areas and will dramatically improve how much (or how little) air infiltration can occur.

We also seal any penetrations left behind from our platform staging and penetrations from plumbing and electrical rough ins.

These efforts also keep any air trapped within the wall assembly (once they are closed in) from circulating and causing convection which can create drafty conditions inside the house.

To conclude, there are many areas that can potentially leak air into the building envelope if left unsealed. Each area sealed collectively helps to "tighten" the house helping to improve energy efficiency, sustainability, and comfort for its occupants.