Community Manager

Is Your Condo Breathing? Why Building Ventilation is Critical

Is Your Condo Breathing? Why Building Ventilation is Critical

If your condo board is planning for a re-roofing project, remind the board the project will not be a success without an in-depth consideration being given to the condition of the building ventilation under the roof. Inadequate attic venting will cause ice dams; energy loss; and moisture damage to the roof structure. Too often roof re-surface projects only repeat the mistakes of the past.

A proper roof project includes a review of the capacity of the soffit and ridge vents based on the new codes; reducing penetrations through the internal vapor barrier; and increasing the attic floor insulation to meet today’s energy standards. This review may best be done by an engineer familiar with the appropriate building science and not by the low roofing bidder.

Seasonal Considerations

We all need to vent. No, I am not talking about Monday morning venting about the bum calls the referee made during the big game. I am talking about venting the attic space in your condominium. I know, most folks think venting is a summer issue, so why talk about it when the snow is on the ground? It is true that an attic only needs one tenth the ventilation in the winter than in the summer to control moisture buildup and temperature, but the winter time also has some unique issues.

First of all, if you or the condominium building committee wants to inspect attics, it is a lot easier on all concerned to be inspecting a cold attic than being in an attic on an August afternoon. Secondly, if repairs are needed, it is better to plan in the winter so that your bid documents are ready for the spring and summer construction season scheduling flurry. Finally, cold weather brings ice dams and heat loss due to poor insulation which are both directly related to ventilation problems.

Building Ventilation Best Practices

There are a lot of myths about what makes good ventilation in an attic. It is not true that rising hot air venting through ridge or gable vents is the best natural ventilation. This is sometimes called gravity ventilation. Tests have shown this chimney effect is negligible when compared to wind movement which has a much higher efficiency and allows for considerably smaller net venting area to be successful.

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Soffit vents are probably the most important of all vents as they can act as both an inlet and outlet for air flow. That is why it is imperative they be kept free of debris or other material that could clog the vents. Without soffit venting the ridge or high gable vents would draw make-up air through the ceiling instead of from outside. For this reason the soffit vent should have at least 50 percent of the vent free area (NFA). This NFA rating is stamped on vent products. A rule of thumb is that the summer ventilation requirement can be estimated by determining the volume of attic space and dividing by 2 which will produce the needed cubic feet per minute (cfm) of ventilation.The difficulty with relying on wind movement is that areas of high and low pressure will change with wind direction thus existing buildings are dependent on the design of the building and its orientation for determining the type and location of vents. The best designs have the outlet as high as possible, such as a ridge vent, and the inlet as low as possible such as the soffit area. To improve this air flow, air chutes are often installed during initial construction or later retrofitted. These chutes are formed plastic channels that are attached to the roof joists and are butted up to the soffit vents to act as a pathway conduit for air coming through the soffit vents. They also serve as a barrier to prevent the attic insulation from clogging the soffit vents.

When selecting replacement vents always seek vents that will have low air flow resistance. They come in either perforated or slotted. The slotted has a reputation of resist clogging by airborne debris. Some ridge vents come with baffles which are designed to draw air out due to the suction developed.

As we discussed, venting needs in the winter are often different for the summer. Winter ventilation is needed to remove attic moisture arising from the living space. It has been found that a great deal of moisture from as low as wet basements and crawlspaces can travel through the house’s floor penetrations serving plumbing and electrical piping. This moist air can then cool its water vapor and condense onto roof sheathing. A well ventilated attic will produce a more uniform temperature across the roof sheathing and thus minimizes warm spots near the eaves that create ice dams from cyclical refreezing of snow or rain on the roof.

In summer, of course, the main problem from poor attic ventilation is heat. Ninety degree weather can create temperature of over 150 degrees in an attic. Heat kills. It can kill your air conditioning budget and reduce the lifespan of an asphalt shingle roof by one half its rated life. So if you start having cabin fever, make sure you vent.

Article written by Jack Carr, P.E., R.S., LEED-AP, Criterium Engineers
Published in Condo Media December 2019 edition
Download a PDF Version of this Condo Media Article

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Solar Panels – Right for your HOA?

Solar Panels — Right For Your HOA?

Solar panels may be an option for your community. Legislative incentives are available in states around the country. 

There is a growing consensus that climate change is real and its consequences will have significant impact on our quality of life and regional economic future. While the cause of climate change may be debated, its potential impact on future generations should not be. So the real question should be, what are we going to do about it?

If part of the solution to climate change is living more sustainably with a goal of zero-carbon power production, condominiums can take a key role in this effort. By the very nature of community living, condominiums reduce our carbon footprint through more efficient use of the land and reduction of construction materials with multi-family building designs. Many urban condos are developed by recycling old buildings that are re-purposed thus avoiding the wrecking ball and waste generation.

Condominiums can take a leadership position to promote more environmental friendly municipal projects ranging from efficient public transportation; avoidance of the consumption of fossil fuels in favor of sustainable electric generation for heat pumps or electric powered vehicles; and waste recycling.

Not only has the price for these PV solar panels been dropping rapidly over the past few years, the methods of maximizing their usefulness in a community environment is becoming more viable with the newest technology allowing both direct and scattered sunlight to create electricity and by use of power inverters so electric power can be directed into batteries or the utility grid to sell back excess electricity. These PV panels can be grouped into arrays called micro-grids that can collect electricity and distribute to not just one user but a community of users.

These micro-grids can be located in a wide range of locations. They do not have to be on top of roofs which are objectionable to many. Instead, they can be located in empty areas around the condo complex. As an example, one of these ‘solar farms’ can feed two buildings with four units in each. Buildings such as these are fueled today by shared propane tanks in the backyard, why not solar arrays?

These types of PV solar arrays can provide electricity to fuel common elements such as the club house; street lights; and hallways light fixtures. Unit owners could opted into becoming a member of a solar farm and own a portion of the panel array (called a share) or they could opt out. Those owners who become members of the array can then improve their current old heating system by converting to an electric, ductless mini-split system producing both heating and cooling which they never had before and adding value to their unit. With inexpensive electrical power available condominiums can consider adding fueling stations for battery driven automobiles further reducing fossil based fuel consumption and fostering cleaner air.

Those condo communities with an interest in using solar power in the future should be following locallegislative events.  It is not too early to form an exploratory committee to review all of the special issues condos will face to implement solar power, as compared to an individual home owner. This research should reach out to other states who are ahead of Missouri’s solar curve.  One good source is A Solar Guide for Condominiums Owners and Associations in Massachusetts easily found on Google.

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Vinyl Siding – or Not

Vinyl Siding ProblemsPerhaps you are on the Building Committee which has been charged by the Board to recommend a replacement siding material for your 35 year old condo. Perhaps you are a property manager whose in-basket is filled with unit owner complaints about vinyl clapboard siding problems in the new condo complex. Whatever the vinyl façade issue is, the future solutions may surprise you.

Vinyl siding materials are everywhere. It is probably the most common façade material in all its forms used on condominiums across the nation, and for good reason. It is quick to install; it is relatively inexpensive; and has an estimated useful life of over 40 years. Most of its negatives are well understood: it can crack or break in the winter time from hail or your grandkids hockey pucks; it can make noise when it’s windy or too hot; colors fade or become chalky over time; and frequent cleaning is required. However, these may not be the issues you may need to face with the current vinyl siding problems.

Solar Attack

This problem can fall in the unintended consequences category. With the issuance of the new building energy codes and the drive to reduce our heating costs and carbon footprint, we are melting our vinyl siding. This is happening due to the installation of the new low-E, highly insulated glass windows being installed in both new buildings and replacement windows.

The thermal layers and reflective properties of these high-tech windows cause sun rays to bounce off and reflect onto vinyl siding causing the siding to buckle; warp; or melt. These new window surfaces act like magnifying glasses concentrating the solar energy on a vinyl surface that cannot tolerate heat over 150 degrees Fahrenheit. This condition can occur when a window on the south elevation of the building is near a right angle corner wall covered in vinyl siding. It can even occur when a new commercial building is built across the street and its new glass wall façade faces the sun and reflects across the street to your vinyl sided property.

So what are you to do? This problem was rare in the past but now solar damage is occurring with increasing frequency due to the drive to install low-E windows. The Vinyl Siding Institute suggests placing awning or shades over the windows and even changing the landscaping to create shade trees to block the light. Some vinyl siding manufacturers are addressing this type of solar damage by adding a ‘thermal diffusion agent’ to the vinyl mix at the factory to help reflect and resist the heat build-up.

Manufacturers are also responding to the problem with vinyl siding by excluding solar refection or melt damage from their warranties. Their warranties always excluded damage from heat sources such as gas grills placed too close to the exterior wall, but now damage from reflective windows is recognized so it would be wise to read the fine print before selecting a siding brand.

Color Fading

This increasing problem is a sub-set of the solar melting problem. Whether it be due to window reflective energy; climate change; or changes in manufacturing, this color fading complaint is becoming more prevalent. In the past, color fade was protected with a lifetime warranty by the manufacturer. Color fade was measured by a maximum of a Delta E of 4 Hunter units in accordance with ASTM standard D2244.

In the past, this warranty issue would be handled by a siding replacement policy. Now, some manufacturers are offering a ‘restore’ process instead of replacement. The ‘restore’ process would allow the manufacturer to paint the siding with an acrylic paint often applied by specialist painting contractors. This restore process comes with a 10-year warranty, down from the prior ‘limited-lifetime’ color warranty. Here again, read the fine print before signing the contract.

Installation

Vinyl siding may be quick to install, but it is not easy, if it is done right. Vinyl siding has an integral vinyl tab at the top in which an oval hole is punched at set intervals along its length to allow a nail to be driven through this hole and into the sheathing. Sounds simple, but it is not. The manufacturer specification requires the installer to drive the nail head within 1/32th of the vapor barrier/ sheathing surface so as not to bind the thermal movement of the siding.

Keep in mind the fasteners are being driven by an adjustable nail gun requiring a level of skill to properly set the nails in each slot hole without touching the vinyl. This accuracy requirement, coupled with today’s reduced numbers of skilled construction personnel, makes this a quality control challenge. If fastener binding does occur, the siding will not properly move with thermal expansion and buckling will soon appear on the surface.

So the answer to today’s vinyl siding problem is: do your research. Read the manufacturer’s specifications and warranties; ensure your contractor is committed to good supervision of the installation of this important building envelope element; and finally, follow up with your own quality verification program, either through your building committee or project engineer. The siding is only as good as it is installed.

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