Tips on deck flooring for screened porch

Posted9/2/2018 6:00 AM

Q. We just saw this decking in the Menards sale flier that came with our newspaper. Maybe we could put this on top of the existing pressure-treated floor at 90 degrees to the current flooring and get a tight seal. This would be good because we are adding storm windows to this existing raised deck/porch (about 4 feet above grade) and this would seal the current floor openings so this one-season room would become a three-season room.

We have heard from a friend who has seen this material warp. I think it is vinyl. This might be less of a concern because it will be on the floor of a covered deck/porch. Another question is can we install this material fitted tightly or is spacing needed for thermal expansion? Or is there a better option?


A. Composite deck materials are getting more common. Even though I have not seen what you propose done before, it may work in your case because the new flooring will be in an enclosed three-season room. I would not recommend this installation in an outdoor situation, as it would trap water between the layers.

Some of these decking materials are installed with a proprietary fastening system that provides a very small space between boards and controls warping. I have seen installations several years old and exposed to the elements without any problems. But it depends on the manufacturing as I have also heard a number of complaints about color retention and warping.

Sometimes experiments work and sometimes not. Best of luck.

Q. I read your column in the Daily Herald. I live in the North suburbs of Chicago. I would like your opinion of three transparent stains. I have been using Sikkens Cetol SRD, available at Menards (photos of the product I am presently using and of the deck today).

The deck was stained in July 2015. Your suggestion is always Amteco TWP. Do you think I would get better performance from this product over Sikkens? One quote I have is using Behr products, which I have no experience with on decks.

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A. The photo showing your deck as it looks today after three years with the Sikkens transparent stain looks quite normal. If you are happy with it, why change? It is better than to try some other product on top of this one; they may not be compatible.

The only experience I have had over the years with Behr and Sikkens stains (never having used either myself or for any clients) is what I have heard from unhappy readers who had used these products on open decks. I haven't heard from anyone who have successfully used them for good reasons because I only hear about problems. But we also need to keep in mind that a lot of bad experiences are a result of poor preparation and application of any coating.

By contrast, I have used Amteco products for 30-plus years, shortly after Amteco TWP came on the market with their Series 100, on the advice of a former Texas Forest Service engineer who told me they had tried every kind of stains on various woods on their buildings and that Amteco TWP was by far the top performer able to withstand the very rigorous challenges of the Gulf Coast of Texas climate.

I have used it and recommended it on cedar and pressure-treated decks, fences, cedar roofs and various sidings with no ill effect, which is why I haven't tried other products.


Q. Our house was damaged by a hailstorm last year. Insurance was to pay for a new roof and siding. We had aluminum which they couldn't match. At the same time, I happened to read your column where somebody had a question about siding and you suggested adding pink boards for more insulation and sound deadening. I did -- cost an extra $1,900. Over the winter I noticed that our family room was cold, so I put a thermometer on the window sill. Below zero outside and it registered 57 degrees on the sill. While I never registered the indoor sill temperature before, the family room never felt that cold. I asked the siding guy about it and he said they had nothing to do with the windows and didn't change anything. Windows are vinyl, as is the new siding, and about eight years old.

Additionally, walking the neighborhood. I've noticed vinyl siding sort of buckling. They assured me that mine would be thick and wouldn't do that. Well, now it is buckling here and there. Now the installer says that's normal with the heat we've had in the Chicago area.

Any thoughts or suggestions would be appreciated.

A. A lot is wrong here. Yes, my suggestions have always been to use 1-inch thick XPS or polyiso rigid foam insulation wherever possible when residing a house as the best and simplest way to increase the energy efficiency of its walls.

XPS is extruded polystyrene and it comes in blue, green and pink as far as I know; polyiso is a urethane insulation. These types of insulation, when properly applied, not only increase comfort and energy savings, but also provide some sound deadening from outside noises. Proper installation is critical; corners and joints must be tight and taped.

Windows can be a great source of heat loss unless they are of top quality; the range in vinyl windows is quite great. Improving the insulation of the outside walls increases the percentage of heat loss through windows and doors.

If I understand you correctly, the windows were replaced eight years ago, at the same time as the siding, but the siding contractor was not the one who replaced them. The vinyl windows may be of poor quality and may have been installed without the required foaming around the frame.

You can try moving a lighted candle around the perimeter of the windows on a windy day to see if cold air infiltrates (take care if you have curtains or draperies). You can also have the installation and tightness of the windows tested by an energy auditor.

It also sounds as if the vinyl siding was not installed properly. Buckling is not a result of the thickness of the material but of poor installation practices. Heat and cold have nothing to do with it.

The siding must never be nailed tightly; it needs to be nailed loosely to allow for expansion and contraction and it should not be tight to any openings for that reason as well. Drip tabs are essential at all window and door heads to prevent leakage behind the siding, and I wonder if this was done properly.

Consider having a home inspector, professional engineer or a contractor experienced in vinyl siding installation check the quality of yours. Serious problems could occur over time.

• Henri de Marne, a former remodeling contractor turned columnist and consultant, is the author of "About the House with Henri de Marne" (Upper Access Publishing). He continues to take questions from readers for this column and his website, Email questions to

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