One huge expense that has affected many homeowners and painters over the last 15 years was the replacement of their faulty LP siding. The class action suit against Louisiana Pacific for selling the faulty siding lasted for years. Many homeowners never recovered money from the lawsuit as the money allocated ran out.

During this period of time a new type of siding entered the market that offered the durability that most homeowners demanded. It was perfect timing for a cement based siding to enter the market. Many homeowners and builders rushed to buy hardiePlank to replace the decaying siding that plagued the housing industry. Finally a siding existed that would probably outlast the owner. Most folks viewed this siding as an answer to prayer.

Most painters in our industry welcomed the siding. Not having to deal with swelling siding that wouldn't hold paint, certainly made our job easier. While most homeowners and painters were excited about this new long lasting siding, most weren't aware that keeping it caulked would become the new problem that everyone would talk about. The problem was and still is: How do you keep HardiePlank caulked?

For homes that have exposure to sunlight and widely varying temperatures, keeping HardiePlank properly caulked is a challenge. HardiePlank expands and contracts a lot under these conditions. Many caulks on the market today simply do not have the elasticity to handle the movement of HardiePlank.

I have seen the expansion and contraction of HardiePlank siding pull fresh caulk apart within 24 hours after application. It's great siding to have on your home, but you better know what you're doing when it comes to caulking all the joints.

You certainly can't be economy minded with your purchase of caulk when HardiePlank is involved, or you will be doing the job over again. Many painters and homeowners alike seem confused when selecting caulk for this siding. Drawing from my direct exposure to HardiePlank and the associated problems of keeping it caulked, I found that using caulks that comply with either ASTM C 834 or ASTM C 920 work. Applying a caulk that falls in this catagory is doing so within the manufacturers written instructions.

I personally prefer using an elastomeric caulk on my customer's homes. Elastomeric caulks are formulated to bond to concrete surfaces. Sherwin Williams carries a product called Shermax Super Stretch Elastomeric Caulk that I find works well with HardiePlank Siding. It has the elasticity to handle the constant expanding and contracting of HardiePlank. All my crews are required to use this product and I see few problems with caulk separation. One common problem that many homeowners find is the HardiePlank itself was installed improperly. At least a 1/8 inch gap between siding and trim should be left by the installer to allow for a proper amount of caulk to be applied. The 1/8 inch gap is in accordance with caulking manufacturers written instructions. (Leave 1/8'' gap at trim and butt joints for caulk.) If less than 1/8 inch gap is available to apply caulk, then the caulk is too thin to handle the amount of stretching it must endure. I have seen Elastomeric Caulk separate where less than a 1/8 inch of a gap existed in the siding joints. Owens Corning also sells a very good caulk for this type application.

The last point I want to make is there are solutions to this common annoyance. As a painter it is your resposibility to deliver a product and service that will last. As a homeowner make sure you discuss your painter's plans on how he is going to solve this common problem with HardiePlank. This action will go a long way toward avoiding loss of time and money.