Roofs, windows and balconies: what Alberta condo boards ask, answered from public sources

Natural Resources Canada's homeowner guide says ice dams start when melt water from snow on the roof refreezes at the overhang. Its preferred prevention is to seal all attic air leaks and insulate thoroughly.

The guide is written for houses. It says ice damming usually occurs when there is a significant amount of snow on the roof, and that an attic temperature above freezing warms the roof sheathing and melts the snow touching it. It also says a self-sealing membrane under the shingles does not stop ice dams but keeps water from leaking through the roof sheathing into the house.

Next step. When ice dams appear, ask the corporation's engineer to check the attic for air leaks and gaps in the insulation.

Sources: Keeping The Heat In

Alberta Municipal Affairs' STANDATA interpretation 23-BCI-023 (January 2026) says the National Building Code (2023 Alberta Edition) requires an unconditioned attic or roof space to be ventilated to promote the transfer of moist air to the exterior. It says limiting the risk of moisture accumulation, condensation or ice dams protects the health of occupants and prevents damage or deterioration of building elements. It applies to residential buildings.

STANDATA variance 23-BCV-017 (September 2025) reproduces Sentence 9.19.1.1.(1) for housing and small buildings (Part 9). Where insulation is installed between a ceiling and the underside of the roof sheathing, the sentence requires a space between the insulation and the sheathing and vents to let moisture out to the exterior, except where that can be shown to be unnecessary. Larger buildings are covered by other Code parts that this answer does not cover.

Next step. Ask the engineer to confirm in writing how these Code requirements apply to your building's roof and attic.

Sources: STANDATA interpretation 23-BCI-023, STANDATA variance 23-BCV-017

Natural Resources Canada's homeowner guide says uncorrected moisture in an attic reduces the effectiveness of insulation and can lead to structural damage such as wood rot or split rafters. It says mould or rot are sure signs of advanced condensation problems, and that heavy frost in the attic calls for checking that ventilation is present and not blocked with insulation.

The guide is written for houses. It advises checking the attic during or just after a cold snap, when condensation appears as frost. Some frost is expected; it counts as heavy at 10 mm (3/8 in.) or more. It says moisture can reach an attic from outside, through failure of the roof or flashing, or from inside, as water vapour carried by air leakage. It says to pay particular attention to water marks on the underside of the sheathing or along rafters.

Next step. Ask the engineer to check the attic during or just after the next cold snap, and to look for water marks on the underside of the sheathing.

Sources: Keeping The Heat In

Possibly for some attics, but Natural Resources Canada says not to proceed without the building inspector's approval. Its guide for houses says closed-cell spray foam applied directly under the roof surface eliminates roof venting and creates a 'hot roof', where the attic becomes part of the heated and cooled space of the house. It says to use only a spray foam contractor who holds certification and is familiar with the process.

STANDATA variance 23-BCV-017 (September 2025) reproduces the Code's venting sentence for housing and small buildings (Part 9), which applies 'except where it can be shown to be unnecessary'. It also reproduces an explanatory note saying recent research indicates venting of attic or roof spaces is generally still required. Whether a particular roof can show that venting is unnecessary is for the engineer and the building inspector.

Next step. Before any spray foam is priced, ask the engineer and the building inspector whether spray foam without roof venting is acceptable for your building.

Sources: Keeping The Heat In, STANDATA variance 23-BCV-017

National Research Council Canada's Codes Canada FAQ says to look and listen for signs of stress. These can include unusual sounds from the roof or supporting walls, visible movement of walls or sagging of the ceiling, and cracking of drywall or plaster. Doors that jam or water leaks after a big snowfall may also be signs.

The FAQ advises an on-site visit by a local expert, such as a building science specialist (typically an architect or consulting engineer), to assess the snow on a roof. It is written for houses and small buildings and gives no Edmonton snow-load values.

Next step. If any of these signs appear after a heavy snowfall, ask the corporation's engineer or another building science specialist to visit the site.

Sources: Codes Canada

National Research Council Canada's Codes Canada FAQ, written for houses and small buildings, says you should never clear a roof yourself and should opt for a qualified and insured snow removal company instead. Where the roof is accessible from the ground, a snow rake can reduce some load, though even then you need to be careful.

That is general safety advice, not an Alberta occupational health and safety rule, and it is not specific to condominium corporations. The 2015 Construction Performance Guide for New Home Warranty in Alberta likewise says normal home maintenance should include professional removal of heavy build-ups of ice and snow, but does not address condominium corporations. The Guide says its views do not necessarily represent those of the Government of Alberta.

Next step. Decide before winter which qualified and insured snow removal company the corporation will call when heavy snow builds up on the roof.

Sources: Codes Canada, Construction performance guide for new home warranty in Alberta

Not always: Section 6(3)(c) of Alberta's Permit Regulation (consolidation current to 20 November 2024) says no permit in the building discipline is needed for re-roofing if all four conditions are met, including roofing of a similar type and no structural change. The City of Edmonton's page on changes to existing buildings says re-roofing with materials of a similar type and assembly needs no permit, but also lists changes to roofs among those that need permits.

That City page covers non-residential and large-scale residential buildings. Its summary does not repeat all four conditions, and neither source defines 'similar type'.

Next step. Ask the City and the corporation's engineer whether your roof meets all four conditions; permits and safety sets them out in full.

Sources: Permit Regulation, Changes to Existing Buildings and Sites

The City of Edmonton's page on changes to existing buildings lists changes to exterior windows among the changes that need permits, and includes installing new windows among its building exterior changes. It does not say whether a like-for-like replacement is treated differently. That page covers non-residential and large-scale residential buildings.

The City's Home Renovations and Basements page, which speaks of houses, says permits are not required for maintenance or minor cosmetic upgrades such as replacing windows of the same size. The same page lists adding or changing the size of a window or exterior door among the common renovation projects that need permits. Which page governs your building is for the City to confirm.

Next step. Ask the City whether a like-for-like window replacement at your building needs a permit before the work goes out for bids; see permits and safety for what the City's pages say about exterior projects.

Sources: Changes to Existing Buildings and Sites, Home Renovations and Basements

Alberta.ca's energy codes page says that if you are replacing existing windows you do not have to meet current energy efficiency requirements, though you are strongly encouraged to use replacement windows that meet the new standards. The City of Edmonton's page on changes to existing non-residential and large-scale residential buildings asks for energy code documents with applications for building exterior alterations if the original building permit was issued after October 31, 2016.

Alberta.ca does not say whether its statement covers condominium buildings. The City does not say whether replacing windows counts as an alteration that triggers the documents, which it lists under Section 9.36 of the National Building Code (Alberta Edition) or the National Energy Code for Buildings, as applicable.

Next step. Ask the City which energy code documents, if any, your window project needs, and ask the engineer whether to choose windows that meet the new standards.

Sources: Energy codes, Changes to Existing Buildings and Sites

CMHC says that if windows are replaced, the location of the wall air barrier needs to be identified so the windows can be sealed to it, giving a continuous air seal across the installation. Natural Resources Canada's homeowner guide lists properly applied flashing among the defences against window and door wall leakage; in its example, the top window flashing goes underneath the air barrier, and the side and bottom flashings go on top of it.

The CMHC statement is from its manual on air leakage control in multi-unit residential buildings, which is aimed mainly at high-rise buildings. The Natural Resources Canada guide is written for houses.

Next step. Ask the window contractor and the engineer to identify the wall air barrier and show how the new windows will be flashed and sealed to it.

Sources: Air Leakage Control for Multi-Unit Residential Buildings, Keeping The Heat In

CMHC's manual on air leakage control in multi-unit residential buildings says testing the first few installations will help to identify any problems with the contractor's sealing techniques and could prevent major problems down the road. The manual does not make this a requirement.

It says a residential blower door can depressurize an individual suite so the rough opening seal between the window frame and the rough opening can be examined. The manual is aimed mainly at high-rise buildings.

Next step. Ask the engineer whether the window contract should provide for testing the first few installations.

Sources: Air Leakage Control for Multi-Unit Residential Buildings

Alberta Municipal Affairs' STANDATA variance 23-BCV-001 (April 2024) says the National Building Code (2023 Alberta Edition) introduced a requirement for a mechanism that can only be released with tools or special knowledge to control the free swinging or sliding operation of openable windows. The requirement applies to windows less than 900 mm from the finished floor and more than 1800 mm from the floor or ground level on the other side of the window.

The variance applies to Part 9 residential buildings. It does not say whether replacement windows in an existing building must comply.

Next step. Ask the City and the engineer whether the requirement applies to replacement windows in your building before the windows are ordered.

Sources: STANDATA variance 23-BCV-001

CMHC's 2003 Capital Replacement Planning Manual lists concrete balcony decks with a low-end average service life of 21 years and a high-end average of 29 years. It lists painted iron balcony railings at a low-end average of 11 years, a high-end average of 18 years and a median of 15 years, and aluminum railings at 20, 30 and 25 years respectively. CMHC says these figures are only a guide.

Those figures come from a survey of building professionals across Canada, using information dated 29 February 1996, so they are not Alberta-specific. CMHC says the table does not replace informed decision-making. The stucco and the building envelope page says more about where the table comes from and who the manual was written for.

Next step. Treat these figures as a guide only, as CMHC does, and ask the engineer what they expect for your balconies.

Sources: Capital Replacement Planning

Under its heading for exterior common elements, CMHC's physical evaluation checklist for buying a resale condominium unit lists that balcony railings are rigid and rust-free and balcony slabs are not breaking up. It also lists exterior walls that are not cracked, corroded or water-stained.

It is a consumer checklist, not an inspection protocol or maintenance standard for a board. It gives no frequency and does not say how cracking or corrosion is to be judged. It is federal guidance, not Alberta-specific.

Next step. Ask the engineer which balcony railings and slabs an inspection will cover and what the report will record.

Sources: Physical evaluation checklist

No. Alberta's Permit Regulation (consolidation current to 20 November 2024) says in section 5 that a permit issued under it makes or implies no assurance about workmanship. The permits and safety page gives the section's full wording and covers whether a permit or an inspection relieves the owner of responsibility.

Next step. Ask who will check the workmanship while the work is done, since the permit gives no assurance about it.

Sources: Permit Regulation

Health Canada's guide to addressing moisture and mould indoors says any indoor mould growth should be removed, but the underlying water or moisture problem should be fixed first to prevent mould from returning. It says the building envelope (roof, walls, windows, doors, foundation) must be repaired if moisture or water is entering from the outside.

The guide treats a single patch of mould larger than three square metres as large, and says immediate action and a professional assessment are required to determine the cause and develop and carry out a remediation plan. MyHealth.Alberta.ca says you may need to hire a professional for foundation, roof or exterior wall problems. Health Canada's guide is not written for condominium boards.

Next step. If a patch is larger than three square metres, arrange a professional assessment straight away, and ask the engineer where the water is getting in.

Sources: Guide to addressing moisture and mould indoors, Mouldy Homes and Buildings