Tag Archives: Gary Sharp

PEER Review - Introducing the Prefabricated Exterior Energy Retrofit Methodology

PEER Review – Introducing the Prefabricated Exterior Energy Retrofit Methodology

Latest News


PEER Review – Introducing the Prefabricated Exterior Energy Retrofit Methodology

As Canada’s existing housing stock ages, more and more homes will need to be renovated – not only to update their looks and adapt to how people use their homes today, but for increased energy efficiency. Our country has 14 million residences, and approximately half of that stock was built before 1985. Given that a home built to code today is 47% more efficient than one from 1985, if Canadians truly want to address climate change within the housing sector, we’re going to have to get innovative.

CHBA and its leading members have been working hard to pursue energy efficiency innovations for voluntary adoption, staying ahead of the curve while advocating that regulation wait until next levels don’t reduce affordability, both for new homebuyers and Canadians who already own a home. When possible, CHBA works with government to find solutions and offer industry assistance for research and development.

One promising approach that is currently being explored is using modular construction technology in renovations. The Prefabricated Exterior Energy Retrofit (PEER) methodology is being championed by Natural Resources Canada (NRCan) and was recently presented during a meeting of CHBA’s Canadian Renovators Council.

Before
Before

After
After

Using PEER technology in renovations

Applying the PEER technology involves four key steps:

  1. The building is accurately measured.
  2. Large exterior, airtight, super-insulated cladding panels are designed.
  3. The panels are manufactured offsite.
  4. The panels are delivered to the site and installed.

Utilizing PEER methodology will bring Canadian-manufactured housing companies together with renovators to create a market for prefabricated, energy efficient façades which can be retrofitted onto existing buildings.

The pictures (on the facing page) illustrate the potential of the process on a simple construction trailer which NRCan presented as a PEER “Proof of Concept” pilot. This gave the researchers a first-hand opportunity to study the construction retrofit process, assess the opportunities for energy performance potential, and determine the practical implications for construction.

This approach to renovation has several advantages:

  • Speed. Once the industry has experience, PEER has the potential to significantly reduce the time it takes to renovate homes and buildings to an improved level of energy performance.
  • Enhanced Performance. The PEER panels can be designed to add significant levels of insulation and improve the overall airtightness of a building. This improves occupant comfort, reduces utility costs, and protects the owner from future escalation of energy fuel costs.
  • Occupant Convenience. Since the renovation is completed largely from the outside, disruption to occupants is minimized. In many cases the occupants are not displaced by the renovation work.
  • Improved Curb Appeal. The renovation provides a complete facelift for the building. With appropriate material selection, the exterior will remain beautiful and maintenance-free for years.
  • No Loss of Floor Area. Many of Canada’s older homes have limited floor space. Occupants will appreciate the fact that the renovation is exterior and does not affect the useable interior floor space.

A Brief Overview of the Process

Measuring the Building

All seasoned renovators understand the importance of accurate measuring. So how close do the measurements need to be? For the position of windows, the window openings (height and width), and the overall building width, each has to be within ¼” (6 mm). Building height from the top of the foundation to the soffit, the average grade to the top of the foundation, and the centerline of building penetrations (including utility meters and service entrances) need to be within 1″ (25 mm).

The options for taking the measurements include:

  • Measuring by hand – This is the lowest cost, but least accurate.
  • Total Station Theodolite – While many of us have never employed this technology, equipment and operators are widely available. It is extremely accurate but does not capture as many points and as much detail as laser scanning. The data is easily imported into CAD drawings.
  • 3D Laser Scanning – This produces detailed datasets but they may be so large they are hard to work with. This approach has a high degree of accuracy. Special software is required to use the data. The scanner has difficulty capturing data from very dark or reflective surfaces.
  • 3D Photogrammetry – This technology uses a high-resolution camera to take pictures of the building, then uses software to calculate the measurements. The accuracy is lower than the theodolite and the laser. This technology is commonly used today for estimating roofing projects using aerial photos taken from planes or drones.

Designing the Panels

The panels include a “squishy” layer for plumbing the panel where it meets the existing building. Panels need to address the insulation requirements as well as airtightness.

PEER Panel Manufacturing

Panels can be constructed up to 24′ (7.4 m) in length. Ideally, panels will be manufactured offsite in a climate-controlled facility.

PEER Panel Delivery and Installation

Completed panels are transported to the site where they are moved into position with a crane. The panel’s weight is supported on brackets attached to the foundation. The panel is then secured to the framing of the existing walls. Panels are supplied as completed insulated wall assemblies including claddings, with windows and doors installed. The old windows and doors in the existing building wall will be removed prior to the PEER panel being installed.

Pilot Projects

The Butterwick Group, a CHBA member company based in Edmonton, is leading a 59-unit pilot project using wood-framed PEER panels to achieve Net Zero Ready. Ottawa Community Housing will also undertake a pilot to retrofit four townhomes to Net Zero Energy using structural insulated panels (SIP) in 2020.

The Time is Right

To address climate change, future renovations will need to involve deep energy retrofits. CHBA members get a leading advantage on new technologies and ways of doing business. And the Association advocates for factors that will hopefully contribute to homeowners’ interest in renovating for energy efficiency, including home renovation tax credits. With the help of government research and development, methodologies like PEER should allow projects to be completed faster, allowing renovators to help more Canadians each year improve their home’s efficiency. It can also help renovators take on larger residential projects that they might otherwise not consider, since PEER is equally applicable to large homes and buildings. All in all, the future looks bright (and energy efficient) for Canadian renovators.

Mark Carver is a Project Leader with the Housing Team at CanmetENERGY, Natural Resources Canada.
Gary Sharp is the Director of Renovator Services at CHBA.

SHARE  

Featured Products


CHBA Connects - Book Smarts

Book smarts – An exclusive sneak peek inside the CHBA’s new renovators’ manual – Apr/May2019

Latest News


Book smarts – An exclusive sneak peek inside the CHBA’s new renovators’ manual – Apr/May2019

As you know from previous columns, CHBA has a Renovators’ Manual in the works. Similar to CHBA’s best-selling Builders’ Manual, the Renovators’ version applies building science to renovations. Existing buildings are going to be important as Canada takes steps to limit climate change. This month we offer a small sample of what readers can expect from the new book, when it is released to the public.

Canada has more than 14 million existing houses. Over half of these were built before 1980. That’s important because these older homes were not built to be anywhere near as energy efficient as houses being constructed today. In fact, a house built today is 47% better in terms of energy efficiency than a house built in 1985.

Building Codes are addressing the energy efficiency of new houses. Current plans are for new houses to reach Net Zero Ready levels of energy efficiency by about 2030. Currently, builders are constructing approximately 200,000 housing units per year. This number has been quite consistent in recent years, although it is expected to slowly drop in the face of an aging population. Some simple math shows us that over the next 10 years, building at the anticipated rate, we can expect between 1.8 and 2 million more houses to be created. While these will be far more efficient than the houses we have now, there is no scenario for reducing the total amount of energy used by homes without addressing the existing housing stock.

The Renovators’ Manual will help with those renovations as renovators are asked to significantly improve the energy efficiency of existing houses. Looking a little deeper, this means that renovators will be asked to “apply” the building science they know to existing houses. This is not as easy as it might seem, since applying building science to the materials and systems that are already installed is quite different than starting with a clean slate when designing a new build. The process also involves combining new materials with the existing structure they are renovating.

Net Zero Ready houses are typically being constructed with R-65 ceilings, R-40 walls, triple-glazed windows, R-35 basement walls, and R-10 under the basement floor slab. They will also have air tightness of less than 1.0 air change per hour at 50 Pa of depressurization (ACH50). Even the most ambitious renovation of an older home would find these performance characteristics difficult to match, but renovators will want to know how close they can come, and how to avoid technical problems in doing so.

The challenge will come from the correct “application” of the building science. The houses that need the most work are expected to be the older ones. Many of these have little to no insulation. Even if these houses have been renovated previously, it is unlikely that the renovation will have added a significant amount of insulation. It will be useful to review the most likely starting condition of the house, for example;

  • 2×4 wood frame or masonry structural exterior walls
  • Little or no insulation in the walls
  • Little insulation in the ceiling
  • Little or no insulation on basement walls or under the basement floor
  • Poor airtightness characteristics (i.e. drafty)
  • Large humidity swings – low in winter and high in summer
  • Large furnace and/or air conditioner
  • No heat recovery ventilator – bathroom fans or windows for ventilation
  • May have a wood-burning fireplace
  • Poor drainage around foundation
  • Double-glazed windows

Other important considerations are the climate where the house is located, and the characteristics of the occupants of the house. A maritime climate has different characteristics than a prairie climate. A house with two seniors has different operational characteristics than a house with young children. As renovators, we can’t change the occupants, so we need to provide a home that suits their specific lifestyle and needs.

In the case of the house described above, lets look at what has been happening over the years since it was built.

  • The house has had little insulation so large amounts of energy has been flowing though the building envelope.
  • The house has numerous holes and air leaks that result in large heat losses, however the benefit of such high air exchange rate is better, if uncontrolled, indoor air quality. If there is a wood-burning fireplace, these typically allow large amounts of house air to exhaust through the open chimney. Even with “tight-fitting doors or flue dampers, the fireplace chimney is generally a huge energy (and air) loss source for the building.
  • Relative humidity in the house is expected to have been low in the winter, due to the high air exchange rate and high in the summer, for the same reason. This would lead to the house being hard to heat and cool, but also uncomfortable.
  • Windows, in particular in the “wet” rooms such as the bathrooms and the kitchen, were likely subject to condensation on the glass in the winter and the shoulder seasons.

When looking at such a typical existing house the first step is to examine the decisions that need to be made. In this case, let’s pick a traditional war-time, Victory Home which are common in many cities across the country.

Blown opportunity: most older homes have little to no insulation in the wall cavities, an obvious first step to improving energy efficiency.
Blown opportunity: most older homes have little to no insulation in the wall cavities, an obvious first step to improving energy efficiency.

General

The renovator will need to decide on the building science features which need to be addressed.

  • If the drainage is poor, this needs to be fixed, regardless of what the house is made of.
  • The basement floor is uninsulated. This will not be a comfortable floor without insulation. It is unlikely that removing the basement floor, adding insulation, and then re-installing a concrete floor makes sense unless the existing floor is in poor condition. Therefore, insulation can only be added to the top of the floor. This will be limited by the basement ceiling height.
  • New triple-glazed windows will be needed to improve the envelope.
  • The wall thickness will need to be increased to accommodate the increased insulation.
  • The key building science features needed:
    • Weather barrier
    • Rain screen
    • Thermal barrier
    • Air barrier
    • Vapour barrier
Historic victory: across the country, many WWII-era victory homes, originally built as temporary housing for industrial workers, are still standing as permanent but inefficient homes.
Historic victory: across the country, many WWII-era victory homes, originally built as temporary housing for industrial workers, are still standing as permanent but inefficient homes.

Victory Home

This house will be wood-frame. It is unlikely that the exterior of the house is historically significant, and therefore the renovator has options. The insulation can be added to the interior or the exterior of the building. While working on the inside of the home is easier, the Victory Home is a modest size and the owners may be reluctant to reduce their floor area. To accommodate this, the decision may be made to add thickness to the exterior. The method of increasing the thickness of the wall studs will be the most problematic decision. This can be done in a number of ways and an architect should be consulted for a suitable solution. Typically, the frame of the existing house is structurally sufficient enough to allow the extensions to be “hung” from the existing walls. If that decision is made, then several items fall into place.

The weather barrier is the exterior cladding. Unless an air space is incorporated into the cladding by the nature of the cladding itself, it needs to be installed on strapping to provide an air space.

The rain screen is the air space between the cladding and the house wrap or the insulation installed over top of the studs.

The thermal barrier could be selected to do “double-duty” by selecting foam insulation which also has air barrier properties.

The selection of the vapour barrier is required. Keep in mind that vapour diffusion is a relatively weak process for moving moisture and is dependent on the surface area covered. If 90% of the surface is covered, then 90% of the vapour diffusion is prevented. Moving air is the primary transport mechanism for moving moisture. If the air barrier feature is being handled by another material, the vapour barrier can be a vapour retardant paint (if the interior drywall was not removed, the vapour barrier may already be in place with the existing, multiple coats of paint). If the walls were opened, there is an opportunity to install a sheet-type vapour barrier. This can be polyethylene, or it can be one of the materials where the vapour permeance changes with humidity. This will allow any moisture which happens to get into the wall due to poor flashing details or poor window installation to dry.

The ceiling can be sealed by removing the existing ceiling insulation and applying two or three inches of spray foam insulation to provide the air barrier properties. The desired amount of insulation can then be blown in on top of this to provide the thermal barrier function.

The basement walls and rim joist space decisions will generally be based on the type of foundation present. The most likely options are concrete block or poured concrete. Poured concrete is considered an air barrier, while concrete block is not. If poured concrete, spray foam insulation may be the best solution for connecting the air barrier in the walls, the rim joists, and the basement wall. If concrete block was used, an alternative such as airtight drywall, a vapour permeable, air barrier sheet material or spray foam insulation against the concrete block wall. Typically, drainage is poor in these older houses so a mechanism to allow these walls to dry to the inside is preferred. A provision must be made to ensure that the air barrier is connected to the concrete floor as well. How to do this detail will depend on the method chosen to provide the air barrier for the basement wall.

Now, with the house better insulated, with better windows and more airtight, the air conditioning and heating systems will be over-sized. If left as-is, oversizing will lead to short cycling and this may lead to inadequate distribution of heat and cooling in the house. Also be aware that with the improved air tightness, mechanical ventilation will be required to eliminate cooking odours and to control humidity levels. Therefore, the renovation should include an upgrade to the heating and cooling equipment as well as adding a heat recovery ventilator.

Hopefully this example highlights some of the challenges that renovators might expect and demonstrates the role the new CHBA Renovators’ Manual will play in helping renovators with the decisions they will be making to improve the energy efficiency of housing across the country.

Gary Sharp, CHBA

SHARE  

Featured Products


rc_march20_fi

March is Ladder Safety Month

Latest News


March is Ladder Safety Month

As we move into the warmer months the projects we work on increasingly have us working at height, whether it’s painting exterior cladding or installing new siding, roofing, or windows. And I can guarantee that we’ve all seen someone do something unsafe on ladder, from carrying a heavy awkward load or leaning out to far, to jumping the ladder across a wall to adjust its positioning.

In the U.S. they’re calling March Ladder Safety Month, and it’s a good time to think about safely working at heights, particularly if you’ve been celebrating St. Patrick’s Day on the 17th.

rc_march20_1
Gary Sharp

Here’s an excerpt with some ladder safety tips from the CHBA Connects column by Gary Sharp coming up in the April/May issue:

In 2015, there were 232,629 workers hurt on the job in Canada; 143,478 were male and 89,151 were female. The construction industry’s share of that total was 26,015 people, representing approximately 11 percent of all injured workers.
According to the Occupational Safety and Health Administration in the U.S., 1 in 10 construction workers are injured every year. The Center for Construction Research and Training notes that falls are the greatest cause of fatal construction injuries. And in terms of where these falls are occurring 39 percent are from roofs, 33 percent are from scaffolds, and the remainder are falls from ladders.
Make sure everyone knows it is important to think safety and it is everyone’s responsibility to be looking out for themselves, but if they see some someone else at risk, they need to say something.
To get it started, here are some simple ladder and scaffold tips to start the conversation.

Ladder Tips

  • Inspect ladders for damage before use.
  • Mark a damaged ladder and take it out of use.
  • Choose the correct ladder for the job.
  • Know the load capacity of the ladder and figure your weight plus the tools and the materials to be supported.
  • Don’t stretch, lean, or otherwise over-extend yourself while working on a ladder.
  • Get off the ladder to move it – don’t “walk” it, or “jump” it into a new position.
  • The base of a ladder should come out from the structure 1 foot for every 4 feet up.
  • Extend ladders 3’ above the level being accessed.
  • Don’t put ladders on top of boxes or use something on a ladder rung to reach higher.
  • Don’t leave tools hanging on a rung.
  • Don’t tie ladders together for more height.
  • Don’t use ladders as walkways or platforms.

SHARE  

Featured Products