What is a green yet economical option for updating old siding?
Our eastern NC home was built in 1933. It has wood board siding that is a bit rough and needs repair. There is also no sheathing whatsoever: just siding, studs, then interior walls that are a mix of wood and drywall! We are on a tight budget but care about our children's health and our planet as well. Repair or replace siding? Should we consider fiber cement board? Should we add sheathing? if so, what? We have very high humidity. Housewrap too? Tyvek or asphalt felt?
I would like to begin by discussing the safety and health of your children.
- Since your home was built in 1933, there is no doubt that within the multiple layers of paint, traces of lead paint exist.
- Take the time to visit www.epa.gov/lead to review the “Renovate Right” literature on the federal law that went into effect in April 2010.
- When choosing a contractor, ask if they are an EPA Lead-Safe Certified Firm and if they will be following the EPA’s Lead Safety for Renovation, Repair and Painting procedures.
Pros and cons of applying new siding over the existing siding
If you are looking for the least costly approach -- and since your house does not currently have sheathing on it -- I would recommend looking into siding solutions that are applied over the existing siding, for the following reasons.
- Removing the existing siding will increase the cost of construction due to the new EPA Lead Safe law.
- Since you do not have any sheathing, removing the existing siding could cause movement in the structure, and cracks may develop on the interior plaster.
- If the siding is to be removed, it must be done in phases so new sheathing can be applied and act as wall bracing from lateral loads. This will add to construction time and will ultimately increase the cost.
Drawbacks to this approach of installing new siding over the existing siding:
- Limits choices of siding material.
- Does not enable you to insulate the existing exterior walls, thereby decreasing your energy costs for heating and cooling.
- The condition of 78-year-old siding may not be ideal as a sheathing material and may not allow for proper fastening of new siding.
A more expensive approach
If cost is not as great of an issue, consider a solution that will produce an energy efficient home as well as an aesthetically pleasing home.
Here are two approaches for you:
1. Properly remove the existing siding in sections, insulate the wall cavities, and apply an APA-rated sheathing and vapor barrier such as Tyvek.
- Look into cement board products. Although they are more costly than wood, they will perform better under extreme conditions and will not be prone to rot from high humidity levels.
- During your research, discuss with your accountant the available tax incentives for energy efficient upgrades. These incentives may help you make your decision.
2. An alternative solution is install a rainscreen over the existing siding.
- This solution would allow you to add an insulation board and a vapor barrier. It would create a ventilation space between the new rainscreen and vapor barrier, allowing moisture to dissipate.
- It would also create a thermal break in the wall structure, minimizing heat loss and gain, which will lower your energy costs.
- The framing for the new rainscreen can be screwed to the existing studs, eliminating the need to rely on old siding as a structural base.
Find a knowledgable contractor
Proceed by interviewing contractors knowledgable in renovations to older homes who are also up-to-date on new trends and materials in sustainable (green) construction.
You can find a contractor in your area using the “Find a Pro” tab at the top of this page.
Ask prospective contractors to prepare an estimate for at least two possible solutions.
If possible, I would highly recommend having an energy audit performed on your home to determine the proper solution. You may find the more costly solution will reduce your energy costs enough to pay for the renovations.
For more information:
Read "I need new siding. What is the best choice considering cost, energy and sustainability?" a Q&A answered by Raymond Pruban.