We Get Greener Kit Cassingham & her Bigger Half

My Biggest Building Mistake

Randy and I had so much fun designing and building our home. Part of the joy was that we hired a fabulous carpenter to do the building. All we had to do was make about 300,000 decisions along the way.

We designed our house to be energy efficient. We also chose water efficient fixtures. We specified sustainable materials were used for our counters and floors. [I'll share all of this in future articles.] Making all the decisions necessary to get a house built, the way you want it, can be exhausting.

That exhaustion led to a few mistakes. We didn't go for low VOC paint, for example, though we used low VOC urethane. I didn't specify low VOC glue for the counter tops either. But the trim was our biggest mistake.

Painted door and window trim was the direction we chose to go. Wrong! Why? Because our builder doesn't like painting wood and doesn't like working with finger joint trim. Yes, it is our house and we should have been able to do it our way, but we were tired. Remember that exhaustion issue I mentioned? I didn't have the energy to stand up against him, so I let him talk me into using MDF -- medium density fiber. Bad time to get exhausted.

My research told me MDF is high in formaldehyde, a chemical I have tried to avoid, especially indoors. That's not the kind of preservative I want in my life. Formaldehyde is toxic to humans -- heck, to any living creature. Why do manufacturers use stuff like that?

Formaldehyde-free versions of MDF were available, but at a much higher cost. When we decided to add crown molding to our list of trim work, the costs really started making a difference. We let our budget sway our decision.

Wood crown molding, even poplar/aspen -- the least expensive trim wood you can buy -- was also more expensive than we felt we wanted to pay. And the builder still balked at painting wood. So we caved.

Our builder assured us that the exposed surfaces would be painted and that would hold the formaldehyde in. Right. I was too tired to fight him on that logic, so I let it slip. Darn it!

The good news is that formaldehyde, which is unstable in air, has a half-life of 10-30 days, probably closer to the 10 days end of the scale. Since we moved into the house in the spring we had a chance to leave windows open much of the time, releasing the polluted indoor air to the outdoors. Most of the formaldehyde had probably off-gassed by the time we closed the house up for the winter. Whew!

The bad news is that MDF doesn't wear well. It chips and scrapes easily. I learned many years later that if you prime MDF it won't scrape easily, but that doesn't impact the chipping. Carrying something through the door that hit the corner of the trim chips the edge, leaving that ugly cardboard color showing. Even the cord pulls on our honeycomb blinds chip the window trip as they bounce in the wind.

MDF is supposed to be dimensionally stable too. Ours isn't. Most seams, especially those on the south side of the house, show because the product has shrunk. The beautiful sea green is punctuated by white stripes where the seams have gapped. That's not really the look I was after.

My strongly stated opinion on MDF is do not use it!! Never, ever. Even if the product is formaldehyde-free and the surface is primed correctly, it's just too fragile for the average home. We use our house gently and it still chips and gouges. What if we had kids or dogs? The trim would most likely be destroyed by now.

Avoid using MDF for environmental and maintenance issues. Don't make the mistake I made. Avoid toxic products that off-gas in your home or office. You can get greener by making other choices.


Good to hear about this stuff. We had to replace door jams after a young puppy chewed one and discovered termites had destroyed 80% of the wood and the paint was holding it together! Very thick paint! Our house was built in 1956 of block and wood, is there anything to watch out for now 54 years later? This is in Phoenix AZ.

Leslie at April 24, 2010 1:09 PM


Do you mean for houses in general, or for door trim in specific? I can't think of any other warnings for trim, though I suppose there are plastic trims that could have offgassing problems, but I don't have experience with them to have anything to say.

I guess my best advice is to find trim made of poplar, if you are painting it, or certified by the Forest Stewardship Council if you are staining it. And whether with stain or paint, use low VOC finishes. (Aha! Another article idea. Thanks!)


Kit Cassingham at April 24, 2010 4:30 PM
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