A few things to watch for during your next renovation (or before purchasing a home):
Aluminum Wiring: With rising copper prices in the late 1960's and early 70's, many builders made the switch to aluminum products. The problem? Aluminum expands and contracts as it heats and cools. This can lead to shorting or even arcing at receptacles and fixtures - a serious fire hazard. There are some products on the market to make aluminum wiring safer however a renovation is a great opportunity to simply remove and replace. The cost? A few thousand dollars to "make safe" existing aluminum and $10,000+ (plus the cost of replacing wall board, paint etc.) for a whole home.
Asbestos: Asbestos was a popular and common additive in insulation, wall board/mud, tile and other household materials for years due to it's exceptional insulating and fireproofing properties. Unfortunately, it is a known carcinogen. Loose asbestos (attic insulation, damaged insulation around pipes etc.) should be properly abated and replaced. Drywall and tile that are not damaged are generally considered safe however any of these materials that contain asbestos must be dealt with specially if removed. The cost? Removing and disposing of asbestos containing drywall from an entire home can run upwards of $10,000. Regardless of the size of the removal, the work should always be conducted by a company specializing in proper testing and abatement.
Lead: A common additive in paint and some plumbing applications, lead can lead to health issues if ingested. Lead containing paint should be removed (particularly if you have small children or animals in the house.) It is unlikely you will find lead-containing plumbing in your drinking water supply lines however, if you do, this should be replaced as well. The cost? It varies. Dealing with a small amount of lead-containing paint can run a few hundred dollars while replacing water supply lines can cost several thousand.
Polybutylene Pipes: Polybutylene (Poly-b) pipes were used extensively as a replacement for traditional copper from the late 1970's to mid 90's. Once billed as the "pipes of the future", Poly-b was found to react with some common water additives (like chlorine) resulting in pre-mature failure. Poly-b looks similar to modern PEX products and therefore may not be easy for some home owners to identify. If in doubt, ask a professional plumber or contractor. The cost? It really depends on how prevalent Poly-b is in the home. If it was used sparingly to replace copper during previous renovations then it is a relatively cheap and quick fix. If, however, it was used throughout the home, the costs could climb to several thousand dollars (still cheaper and more convenient than fixing the damage caused if it fails)!
Siding: Common practice was always to frame-up a house, nail-up some plywood, throw on a layer of tar paper then affix siding directly over top. The problem? Any moisture that gets behind the siding is essentially trapped. When the wood can't breathe, it can't dry and this can lead to significant rot and mold issues. Best practice today is to install a rain-screen system between the sheathing and the siding. This process allows air to circulate: removing water before it has a chance to damage wood. The cost? Rain screening in conjunction with replacing existing siding ads very little to the overall bill. Retrofitting existing siding however can be a very complex process involving the replacement of windows, flashing and often the siding itself running the bill up to thousands of dollars.
Wiring - Kitchen: Electrical codes have been updated many times over the years. What many people don't realize is that, in almost all cases, wiring must be upgraded to current code in any area undergoing a substantial renovation. Electrical requirements in the kitchen are a great example. In BC, the oven, microwave, sink disposal unit and refrigerator must each be on their own circuit. Outlets are limited to a maximum of two per circuit (upgraded to 20 amps) and all kitchen electrical must be fitted with Arc and Ground Fault protection. The cost? In conjunction with a complete kitchen renovation, the additional costs are a few hundred dollars in most cases. The electrician may need to run wire back to the electrical panel and replace (or add) breakers which could increase the cost further.
Tar & Gravel Roof: Many homes were (and still are) constructed with roof slopes too flat for shingles. The common solution used to be the application of tar and gravel. The "tar" is actually an asphalt derivative applied with layers of tar paper directly to the sheathing. Gravel is then raked over top to protect the bottom layers from UV damage. The main concern with this type of roof is that it is prone to leaks. As the surface expands and contracts, areas around flashings can open allowing moisture to penetrate. There are still some roofing contractors who work with these materials and can perform repairs if required. However, if your tar and gravel roof has sprung a number of leaks or is more than 15 years old, you might want to consider replacing it with a torch-on membrane. The cost for small repairs can be as little as a few hundred dollars and a complete replacement could cost ten thousand or more depending on the roof area. Additional work may be required including replacement of sheathing, flashing, vents or fascia.
If you have (or are looking to purchase) a home that is more than ten years old, take a few moments to look for signs of these and other potential hazards. A good contractor or home inspector can identify areas of concern and provide you with a remediation estimate