We have a cottage in the Lake of the Woods area and want to replace the vinyl siding. We are considering the cement based product by James Hardie but have heard there may be issues, such as mould and discoloration, at the lake with a product that requires extensive caulking.
Moisture damage to siding and the exterior of cottages in lake country is a very serious consideration when planning construction or renovations. The wrong choice may cause you to spend countless weekends cleaning, scraping and refinishing the exterior to prevent rot. Vinyl siding, while being an excellent siding material for moisture resistance, is often considered to be “cheap” in appearance. I will try to answer your question about a product that has only gained favour in this area over the last few years, but is very popular south of the border.
James Hardie siding is a fibre cement-based composite material that is designed to imitate older wood siding. It may be available in pre-finished form but often is installed and painted, much like the wood siding it is copying. It is much more durable than wood, and virtually moisture proof, when properly installed and finished. This will make it an ideal material for a very high humidity region like lake country, but it will still require regular maintenance and painting.
According to installation instructions and technical information on the James Hardie website, www.jameshardie.com, the siding should be caulked at all joints and openings. This is mostly around windows and doors, and is similar to the requirements for wood siding or other siding materials. If pre-finished siding is purchased, matching caulking should be available that will adapt very well to the siding. If the common pre-primed siding is used, it will require finishing with a top coat, and any caulking could be painted to match.
Vinyl siding is one of the few products that comes with its own trim pieces, often not requiring caulking due to the design and allowances for expansion. That is not to say that vinyl siding does not require caulking. Almost anything that protrudes from the siding or requires an opening in the siding should be caulked to prevent leakage. Regardless of the choice of siding, it is only as effective as the wall assembly behind it when it comes to moisture resistance. Any siding material will require a building paper or housewrap layer over the wall sheathing, behind the siding, to prevent wind driven rain and moisture that gets behind the siding from leaking into the wall cavity. If you do replace the siding, ensure that this critical component is in good shape or replacement will be required at the time of upgrade.
I am not sure where your concern of caulking contributing to mould comes from, but it is likely unfounded. Good exterior caulking is quite moisture resistant, and if moisture does not penetrate a building material there should be no mould growth. You may be confusing the mould build-up on typical bathroom tub/shower silicone caulking as being a problem. Silicone caulking should not be used for this type of exterior application as it can’t normally be painted and is subject to deterioration from UV rays from the sun.
As far as discolouration, good quality acrylic caulking or other exterior rated products can be painted with the same finish as the siding, so they will become virtually invisible after painting. If caulking is done on pre-finished siding, it would be wise to purchase the accompanying coloured caulking so that little differences are visible.
Whatever your decision about an upgrade to the siding, ease of maintenance should be a strong consideration. Vinyl siding or a natural material like stone or brick veneer may require the least maintenance, but may not provide the appearance you desire. For a wood siding look that requires only regular painting, with little chance of deterioration due to moisture, the Hardie siding may be ideal. Care should be taken when cutting this type of siding due to composite materials in the siding that may cause health problems. Ensure that installers are well versed with this product and follow installation instructions closely.