Jean wrote:

Need your expert advice please if you can.  I have installed acres of 18mm solid wood flooring in all my rooms. this winter with the heating on it seems to be shrinking. Seems to be taking wooden studding with it, i.e., door frames fixed on top of it have moved too. Will this settle down do you think?  Many thanks in advance.

My answer:

This shrinking is due to the wood losing moisture content. The indoor relative humidity is usually quite low in the wintertime. As the air dries out, it draws moisture from the wood floors and the rest of the wood in the house, studs and doors included. When the weather warms, the relative humidity will go back up and the wood’s moisture content will increase. The wood floors, studs, joists, and doors will swell up again. If the wood was excessively moist when installed, it will never return to the original size. If the wood had the proper moisture content when it was installed, it will return to its original size. It’s impossible for me to say without knowing the condition at the time of installation.

Seasonal shrinkage of wood in a home is a normal occurrence. One way to reduce this shrinking is to add humidity to your home. A central humidifier installed on your heating system will work if you have forced air heat. Otherwise, a free-standing humidifier would help. If you install or start using a humidifier, it might take weeks for the wood to absorb enough moisture to make a visible difference in the shrinkage you see.

If your floors do not return to normal and excessive cracking is still a problem next summer, call your contractor and tell him you think he installed a wood floor with too high a moisture content. Hopefully he’ll stand behind his work.

Read more about many home design and building topics at my other site, www.about-home-design.com.

But another rule in laying wood flooring has to do with the aesthetics or look of the flooring. As a general rule, wood flooring looks best when running in the same direction as the longest dimension of the room. For instance, if the room is ten feet by sixteen feet, the wood flooring will look best when running in the sixteen foot direction. The narrower the room, the more important this is. So in a hallway that is only four feet wide, the wood flooring really needs to run the length of the hall and not crosswise, if at all possible. In rooms that are more square in shape, the direction of the wood flooring is not as critical.

Also consider the view you have of the floor when you enter the room. The wood flooring looks best if laid perpendicular to your view direction. This will disquise the cracks between the planks. If you are looking straight down the planks, the seams between the boards will be more obvious. And if the seams are not perfectly straight, you will more readily see that variation, too.

It’s not always practical to run the flooring in these optimal directions. But if you can do it, the benefits are real. If the floor joists below the wood flooring are running the wrong direction for the way you want the flooring to look in the room, ask your builder to install wood blocking beneath the floor from joist to joist to support a floor running parallel to the joists. This will cost a bit more, but it will be worth it in narrow spaces, like hallways.

Of course, selecting the right wood for your floor is very important. Consider the grain and color of the wood and how it will look with other wood items in the room, like kitchen cabinets and wood trim.

One other neat feature is to install flush thresholds between rooms. I show photos of this and describe it in detail in my book, Designing Your Perfect House.

If you would like to read more articles about house and home design, please visit my other website, www.about-home-design.com.

Concrete “flatwork,” that is, concrete poured in slabs for floors, sidewalks, driveways, and roads, is particularly prone to cracking. It will shrink as it “cures” and crack. And it will continue to swell and shrink when it gets warmer or cooler and be susceptible to developing more cracks.

There are measures you can take to reduce the chances of cracking. Control joints and expansion joints can be placed in the surface. Expansion joints are gaps purposely placed and filled with flexible material. Treated wood strips, cork strips and caulking are commonly used. The flexible material “gives” when the concrete moves and takes up the dimensional change, preventing cracking. Expansion joints are usually only placed in large expanses of concrete.

Control joints are smaller grooves placed in concrete. These are placed minimally at ten foot spaces or less. The idea is to place them to create approximately square panels so the expansion and contraction of each segment is about equal in each direction. So a four foot wide sidewalk might get control joints every four feet. Control joints actually weaken the concrete at that spot with the idea being that when a crack occurs, it will occur within the control joint and not be visible, irregular, and unsightly. Of course, we have all seen plenty of concrete slabs that have cracks running right along side a control joint, completely ignoring the groove they were supposed to follow. So this is no surefire method for avoiding cracks.

There are no good ways to fix concrete cracks. They are usually irregular, jagged lines. Filling them with caulking will keep water from filling the crack and increasing the damage as it freezes and thaws. But the crack will remain visible and even be accentuated by the color of the caulking. You can chop out the cracked portion of the driveway or walk and replace the concrete. The problem with this is the new concrete will always be a different color than the original. So the patch will stand out.

But leave it to the innovators in the world. There may be a cure, at last. Check out this video on Bio-Concrete.

This clever young man has added bacteria and food for the bacteria into concrete. When a crack occurs, the bacteria start growing and build a calcium based filler in the concrete that is strong, keeps the water out, and is much more visible discreet than any other filler you could use. I can’t wait for this to hit the market.

My son, Matt Hirsch, told me about bio-concrete. He also works with bacteria. Only his bacteria are a relatively newly discovered type that can remove nitrates from ponds, lakes, and streams. I believe him when he tells me that microbiology holds many keys to a better world.

If you would like to read more articles about house and home design, please visit my other website, www.about-home-design.com.

We are starting to select the different materials around the house.  Your beautiful pictures have been a great inspiration…  I particularly like your wooden floors on pages 114

Page 114 Photo from "Designing Your Perfect House"

and 194. 

Page 194 Photo from "Designing Your Perfect House"

Do you happen to remember/can you recognize the kind of wood they are made of?

Here’s my answer.

The wood floor on page 114 is Santos Mahogany. You can see another view of that flooring on page 150. It looks a bit different from one photo to another depending on the direction of the light. Santos Mahogany is one of the few woods that actually gets lighter when exposed to light. The wood you see in the photos has been in place since 2002. So it has already lightened.

The wood flooring on page 194 can be seen again on page 226. This wood floor is Jatoba. It is also known as Brazilian Cherry. But keep in mind that what is often sold as Brazilian Cherry is actually an assortment of pieces of three different species. Jatoba is one of them and I do not know what the other two species are. But some of the pieces of the other species can tend to look a bit greenish. So if you want the redder color, specify that all of the wood must be Jatoba without any other species included.

I always welcome questions and comments concerning anything related to house design, homebuilding, and remodeling. if they are questions i think other reader might like to hear, I’ll post them in my blog.

If you would like to read more articles about house and home design, please visit my other website, www.about-home-design.com.

Gaps between boards, or cracks, if you will, are not the result of the wood floor failing or falling apart. They are the result of the wood planks shrinking as the relative humidity goes down and the wood floor loses moisture content. The air in the summer has a higher relative humidity than in the summer. This lets the wood flooring absorb moisture and swell. So usually gaps between boards go away in the summer. Then those gaps reappear in the winter as the humidity goes down again.

If your builder had installed the floors with too little moisture content at the time of installation, when the relative humitidy went up, the boards would have nowhere to swell or expand and they would push against each other causing the planks to cup and possibly rise. Flooring must be installed to allow this seasonal swelling and shrinking.

If you have standard, 2 1/4″ wide flooring, you should not have gaps wider than the thickness of a business card. However, sometimes two or three boards will stick together and move as a unit. This would produce one crack the width of the thickness of three business cards instead of three cracks, each the with the thickness of one business card. This would be considered normal. If you have cracks wider than that, chances are the floor was installed with too high a moisture content.

If your flooring consists of wider planks, your gaps will be proportionately wider. The wood will shrink the same percentage, but the actual dimension of the crack will necessarily be wider. Planks twice as wide will produce gaps that are twice as wide.

Engineered flooring shrinks less than solid wood flooring. This is because engineered floor has a solid wood surface, but the underlying wood is actually plywood. Plywood is dimensionally more stable because it is assembled with the wood grain of each layer running ninety degrees to the layer above and below. Wood shrinks across the grain and not much with the grain. So one layer reisist the shrinkage of the neighboring layer. If you want wide plank floors, take a hard look at engineered flooring. It will remain much more dimensionally stable than solid wood planks, yet the surface, the part you see and walk upon, will be identical to the solid plank.

Filling the gaps is merely a temporary cure. When the wood swells again as the season changes, chances are the filler will be squeezed out. My recommendation is to look around at older houses and observe the gaps in those floors. It’s likely you looked right past those blemishes and maybe even viewed them as part of the “patina of age” and thought they enhanced the charm of the house. Your house will develop it’s own patina and grow more charming every season if you let the nature of wood take its course. Your wood floors are a natural product that abides by the laws of nature. Swelling and contracting with moisture content is the natural behavior of wood.

I always welcome comments. Please feel free to post a comment and share your experience with the rest of us.

If you would like to read more articles about house and home design, please visit my other website, www.about-home-design.com.