Construction - DIY Concrete Wall Insulation

A recent post delt in part with the construction of the concrete east wall of the future

garage pictured at the left with the French drain at its bottom.  It needed to be insulated exteriorly then backfilled to almost half of its height.  Here I am using that wall to demonstrate a DIY custom insulation method that I will be using subsequently for those parts of the north and west walls that lie above the horizontal insulation/watershed umbrella. (There is no need for insulation below the umbrella so as to maintain as much uninhibited earth contact as possible.) The method I am using was somewhat described in another post in conjunction with the first retaining wall west of the house. What follows is a more detailed account. Remember that a click on any photo enlarges it for better viewing.

Acknowledgement
The DIY design described here is a bastardization of the proprietary product Insofast.  Perusal of the Insofast website was encouraging -- the product would seem to be perfect for insulating our concrete walls inside and out. However, for our  requirements, their quote was at least $3,000 more than the following DIY method.  And Insofast maxes out at an insulation thickness of 2.5", which would have worked for the garage, but not very well for the house. Nevertheless, I am indebted to Isofast for stimulating improvisation.

Overview
Essentially, the insulation is expanded polystyrene (EPS) (styrofoam) supported by metal drywall track (ordinarily used as the bottom member of a metal stud wall, i.e., the part that is fastened to the floor).  Even though the track is galvanized, there would be a limit as to how much moisture it could endure before rusting so I am wrapping the entire assembly in plastic sheeting to isolate it from the concrete on one side and from the outside environment on the other side.  The secondary function of the track is to support the cement board cladding that serves as a base for the stucco finish.

From my drywall supply company, the track comes in two widths -- 2 1/2" and 3 1/2" -- and two gauges -- 20 and 24.  For the garage where maximizing the R-factor is not critical, I used 2 1/2".  For the house walls, I plan to step up to 3 1/2" track for a higher R-value.  As for thickness of the track, the thicker 20 ga is more suitable for supporting the heavy stucco wall.  It then takes two thicknesses of  foam board --
1 1/2" and 1" -- to fit the 2 1/2" track. The plastic sheeting is good quality 6 mil that I buy from a farm supply store in 24' widths -- the kind sold to farmers probably for covering hay. 

My original intention was to use one thickness of 1/2" cement board but, after finding that it was not rigid enough to support a thin layer of stucco, I used two thicknesses. Even two thicknesses would be too compressible and would have to be backed up by something more rigid for long term durability in high traffic areas.  In our case, most of the insulated concrete walls will be below grade after backfilling and most of those above grade are away from high traffic areas.  The lone exception is the east wall discussed here; it will be in a high traffic area but less than half of it will be exposed.

Therefore, I covered the top of the first layer of cement board with a pressure treated 1 x 6 and butted the second layer of cement board up against it.  Not only does the 2 x 6 make the top of the insulation more rigid but it also widens the wall by 1 1/2" which will work better with the stick-built truss wall above it.

Shop-Made Tracks
The drywall tracks that support the insulation and the cement board were shop-made

Drilling holes for the Tapcon screws 

ahead of time.  All but the first track at the south end of the wall and the last track at the north end have to be back-to-back.  Before screwing them together, one of them was

Pre-made tracks already cut to length for the north garage wall

perforated on one of its short sides with holes large enough to accomodate the 3/16" Tapcon screws that fasten them to the concrete wall.  The drill press and a long wood block cut from a 2 x 4 to fit inside a track and marked to guide hole placement made short work of holes drilled 8" apart, which was more frequent than necessary but it gave more options for screw placement during installation.  Next, the pre-drilled track was clamped  back-to-back with another track and the two of them screwed together with metal screws in pre-drilled starter holes.

Screwed-together double track showing holes for Tapcon screws in the bottom piece

Jumping ahead to the time when the tracks would be fitted to the wall, let me share what I found to be the best way to cut them to length.  Use straight-cutting metal shears to cut all four short sides at the cut mark.  Then, instead of trying to cut across the long dimension of the back-to-back tracks, simply to bend the tracks back and forth a few times to "worry" the metal into separating.

Pre-cut Foam Board
Purchasing ESP is cheapest in 4 x 8 sheets but, to fit the present situation, the sheets need to be split lengthwise into 24" pieces.  I have sawed them by two methods and prefer one over the other for the sake of accuracy. The less desirable method is to use a straight edge guide and a circular saw.  Accurate cuts are difficult for several reasons that I will leave up to the reader to find out for him/herself.  The other method is to get someone to help run the sheets through a stationary saw against a proper rip fence. For this, I have used both my table saw and my radial arm saw.  (The latter works for me because the saw table is quite long -- 16' -- which is atypical for arm saws.) Either saw does a splendid job of making a mess of the shop, so I recommend planning ahead and cutting as many sheets as possible in one session to minimize the number of times the mess has to be cleaned up.

The advantage of using a stationary saw is that the sawn edges are straight and each piece is a standard width.  The straighter they are the better they fit the tracks and the less air space exists between the foam and the track.  Air spaces are also minimized by having consistent and matching widths of the two pieces of foam that go together to fit the track.  I had some 1 1/2" foam pieces left over that were cut with the circular saw for the west wall behind the retaining wall.  When they were matched with the 1" that were cut with the radial arm saw, there were air spaces up to 1/2" in some cases -- which was acceptable for a garage wall but would not be for the house walls.  And a stationary saw is mandatory for accurate cutting of thin sheets like the 1" due to the foam's flexibility (even when they are doubled up to increase rigidity).

The pre-cut 1" and 1 1/2" foam panels are easier to cut to length and install between the tracks when they are glued together.  Accordingly, a spray adhesive specific for EPS did the trick.  Just be careful that the edges are flush when gluing. 

Installation of the Track and Insulation Panels
In order to protect the track from moisture, the plastic sheeting must be in place before the

Plastic sheeting covering the near side of the wall;
remainder thrown over the top of the wall temporarily;
 four tracks installed supporting four courses of insulation

first track is installed.  The 24' width of the 6 mil plastic sheeting was a little more than the length of the wall so all I had to do was cut a piece from the roll that was a couple of feet longer than twice the height of the wall.  It was draped over the wall so that it reached the ground and turned outward a foot or so on the near side of the wall.  The balance of the sheet went over the top of the wall and hung down on the far side temporarily. The plastic was left long towards the south (left) end of the wall so that later it could be folded under the cement board in such a way as to protect the left side of the first track.

Tracks and insulation installed, ready for cladding

The south corner track, a single member rather than back-to-back, was cut to length and screwed to the wall through the plastic using a hammer drill, drill/driver and 
1 1/4"  x  3/8" Phillips head Tapcon screws. The first section of foam was cut to length and fitted into the single track, in this case, to the left.  The next (double) track was then slipped over the right side of the foam and pressed by hand or even tapped with a block of wood and a hammer so as to eliminate as much as possible any air spaces between the foam and the left and right tracks.  It was installed with the track having pre-drilled holes to the right. While holding the track firmly towards the left, the right track was screwed to place through the plastic sheeting.  The remainder of the sections were installed in a like manner.  At the north end, the plastic sheeting was folded back over the last track to protect it from the right side.

Installing the Cement Board

Sheet plastic folded back over the wall so as to protect
the tracks and insulation from the exterior environment;
first layer of cement board partially installed 

The cladding comprised the cementitious (cement) board and a top coat of stucco both of which will always absorb some moisture from the environment. So the plastic sheet was brought back over the wall to cover the top of the insulation, hang down in front of it and extend over the French drain at the bottom so as to separate completely the insulation and tracks from the cladding and direct any running moisture to the drain.

Unfortunately, the cement board comes in 3' x 5' panels which doesn't equate well with the tracks on 24" centers.  So they had to be cut to width as well as length which is best done with a nibbler rather than a circular saw in order to avoid the noxious and health-impairing dust.  My nibbler was originally purchased for $80 on Craigslist at a time when I thought I would be gladding the exterior of the house with fibercement board (which later morphed into preference for steel siding which will require a different nibbler). It wasn't until later that I found out that I was lucky to have the fibercement nibbler because it cuts cement board as well.

The installation of the board was time-consuming.  In order to hang it with the same

One-by-six in place; second layer of cement board
butted up against it and ready for parging with stucco

cement board screws that are used for fastening the board to the bathroom floors and shower wall studs, pilot holes had to be drilled in the metal track.  And in order to keep the twist drill sharp for the metal, holes had to be drilled through the cement board first.  This meant three tool changes -- a cordless drill with a 3/16" masonary bit, a cordless drill with a 1/8" twist drill and a drill/driver for the screws.  

The mismatch between the cement board sizes and the 24" OC of the tracks created multiple left-over pieces.  Since I knew that there would be two layers of cement board, I didn't hesitate to work the small pieces into the wall for the first layer even though they were not as rigid as large pieces.  The 3' x 4' second layer pieces covered up the multiple seams of the first layer and added rigidity.  

Adding the Stucco
Fortunately, parging the cement board with stucco was easy after my experience with fiber bonded cement for the dry-stacked block walls of the solar connector.  The material that I

Wall after stuccoing; French drain covered with a layer of
 clean rock; about half of the wall will be buried in
backfill starting with +/- 4' deep at the north corner and
ending with +/- 2' deep at the south corner 

used was Quickcrete Professional One Coat Fiberglass-Reinforced Stucco.  And, as with the fiber bonded cement, getting the consistency just right is critical for easy handling. If it is too dry, it falls off instead of sticking to the wall and, where it does stick, tends to be too thick.  If too wet, it falls off and, where it does stick, tends to be too thin.  With a little experience, the right consistency goes on easily a trowel-full at a time (painfully slow) and can be troweled to a rather smooth finish. The manufacturer recommends limiting the size of each mix to that which can be applied in one hour.  An 80 lb bag mix was about right for meeting the time requirements during the hot summer after I waited to start the project in the afternoon when the wall was in the shade.

It is mandatory to keep a hose or sprayer handy.  Whether the substrate is concrete, other stucco layers or, as is the case here, cement board,  it must be kept moist for the stucco to adhere properly.  And the stucco should be kept moist for a couple of days afterwards to control crazing due to shrinkage as it cures.

In the present situation, both layers of the plastic sheet were trimmed so as to overlay about half of the top of the French drain so that any moisture between the inner sheet and the wall or between the outer sheet and the cladding will be directed to the drain but without completely covering the drain with plastic.

Interior Surface of the Concrete Walls
The east wall of the garage used here as an example and all of the concrete house walls that are insulated on the exterior will be insulated on the interior in a similar way using plastic sheeting, metal track and ESP foam board.  The only difference will be drywall for cladding instead of parged cement board.   

Insulating both sides of the wall will give a nominal R-20 for the garage where 2 1/2" tracks were used and R-28 for the house walls where 3 1/2" tracks were used.  An R-20 for the garage is probably overkill but an R-28 for the house is marginal compared to the R-50-ish stick-built walls and ceilings.  Fortunately, I can live with it since the amount of concrete that will be exposed above the insulation-watershed umbrella will be minimal. 

Backfilling Against the Wall

Provisional backfill to ward off the runoff from behind the wall;
the carpentry  work can now resume  in earnest

The reason for interrupting the carpentry phase and concentrating on the garage wall was to insulate and clad it so it could be partially backfilled to force the runoff from the the backfill behind the house away from the east garage wall and to cover the French drain.  Accordingly, I dropped a few track loader buckets of dirt against the wall to suffice until the entire slope could be properly contoured eventually.

Odds 'N Ends - Work Attire (Cont'd)

Work Boots

Except for hunting, I always bought cheap boots.  They were not very supportive, especially when standing on a ladder or stepping on a nail, were usually so wide that, even with heavy socks, almost needed to be double breasted where they laced and they wore out quickly.  In anticipation of doing construction, I went to a large boot emporium and

My sticker-shock boots 5 years later

threw myself on the mercy of the court, saying something like, "I want to buy a good boot like professional contractors wear", and added something out of character for me, "price is not an issue".  Without hesitation the clerk took me to the Carolina boot rack and picked out a pair of short boots that cost just south of $180 (gulp! that is five times more than I had ever paid for expensive dress shoes back when the dollar was worth something).

Best decision I ever made.  The boots came in more than one width so fit was no issue.  There was no breaking-in period; they were comfortable from day one.  And they have special mid-sole construction to cushion the feet against ladder rung pressure.  As I was coughing up for them at the checkout counter, I ask the clerk, "How long can I expect theses boots to last if I wear them daily?".  She said, "About a year".  I did the math -- that's fifty cents a day if I wore them every day for 365 days.  Well, for whatever reason, she was way conservative because the boots are still going strong after five years.  And, believe it or not, the original boot-strings are still in them.

Making Boots Last
Seems to me that my investment in boots paid off for two reasons -- keeping the leather supple and protecting the toe from wear.

Growing up in the country, I was early on familiar with neatsfoot compound, an oil-based product available at most hardware, work shoes and shoe repair stores.  We used it on tack -- halters, bridles, saddles, harnesses -- as well on leather footwear. It waterproofed the leather and kept it supple.  I had used it in adult life, on hunting boots primarily, so there was no hesitancy about applying it to my new work boots and I am sure it alone has added several years to their longevity.

I think it is safe to say that the toes of most boots wear out first due to scraping on rough surfaces while working on hands and knees.  If the toes can be preserved, the life of boots

Kind of wear Tufftoe prevents

can be extended.  There is an after-market product called "Tufftoe" that is easily applied by the consumer and is offered as a service by some shoe repair and boot stores (our local bootery will apply it for $15 which is about what it cost me online for the product and I had to apply it myself).  It coats the toes with a tough rubbery material that sticks like glue after the leather has been properly prepared for it and protects the toes from wearing out.  I would recommend a visit to the Tufftoe website if you have boots or athletic shoes with vulnerable toes.  A word of caution however:  If you are doing both neatsfoot compound and Tufftoe, be sure to apply the Tufftoe first so its bond with the leather is not compromised by the oil.  Notice in the

third photo that the Tufftoe is peeling away on the top edges due to my having applied it after neatsfoot oil treatment. That said, I took the boots to the original emporium to be sure the the same model of boots would still be available when the old ones wear out and the clerk said that a certain amount of peeling can be expected in any case due to flexing of the leather over the toes.

Gloves

Seasoned construction workers have tough hands because they are typically young or

younger and have skins thick enough to protect against injury. Unfortunately with age, the skin thins out and injures easily. Consequently, I have had to wear gloves year-round and have experimented with several iterations.

Latex coated work gloves have proven to be the most useful --  both the warm weather variety shown here and the heavier colder weather variety.  The amount of dexterity they afford is amazing.  I have no trouble picking up small nails or washers and yet they are thick enough to protect against most injuries.  The heavier winter type are almost as dexterous but, unfortunately, are not thick enough to protect against severe cold.  Another advantage to the latex coating is that it reduces the amount of effort necessary for carrying heavy objects.  The friction between the latex and the surface of a heavy object frees up muscle power, that would otherwise be used for grasping, and reallocates for carrying the item.  If there is a knock against wearing most gloves is that they sometimes catch in the threads of drywall screws such that the glove on the non-dominant hand wears out fastest.

Health Issues

In the previous post, I advocated long sleeves, long pants and a broad brimmed hat as the best way to stay cool in hot weather.  Such a get-up is also important year-round as the best protection against basal cell skin cancer, which increases in frequency with age due to long-term sun damage.  I didn't cover up while young and have paid for it with more than a dozen basal cells removals in later life.

Wearing long sleeves after the skin thins with age affords some protection against scraps and bruises to the arms.  According to my dermatologist, my skin would not be so susceptible to laceration if it weren't for the sun damage in early life.  UV rays seemingly break down the attachment of the outer layer of skin (epidermis) to the inner layer (dermis) such that the epidermis literally peels away from the dermis with the slightest insult.  And the blood escapes not only through the wound to the outside, but also spreads laterally between the two layers of skin and produces ugly bruising.  So, young workers that go shirtless or work in short sleeves are not doing themselves a favor if they anticipate putting their skins in harms way late in life.

Sun glasses are important as well, not just to keep from squinting, but for long-term eye protection.  Solar radiation over time is a major contributor to cataracts.   

Odds 'N Ends - Work Attire

Staying Cool During the Summer

So far, our St Louis summer has been hotter than last summer as measured by

heating-degree days. However, I am pleased to say that, while the hot weather slows my pace somewhat, I am still able to get in 9- and 10-hour days in 90+ degree weather -- weather that is made even worse by the high humidity that rises up the Mississippi River valley from the southeastern states (we are in the "hot-humid" zone that's orange on the map.)  I am pretty sure that my productivity would suffer if I hadn't learned from my elders how to dress for such weather.

"Farmer Attire"

Growing up in a small central Illinois community, I knew a lot of farmers.  Most of them, particularly the older ones, wore denim overalls, long sleeve shirts, "clod-hopper" boots and either straw hats or "gimme" hats.  (Gimme as in asking the seed or implement dealer, "Gimme one of them hats".)  Many of them also switched to cotton long underwear in summer after having worn wool in the winter.  They sometimes didn't smell so great in July but they knew how to beat the heat.

By contrast, you typically see construction workers today wearing shorts and tee shirts or no shirts.  Which do you think is more comfortable in the heat and humidity -- the farmers I knew or today's workers?   Having worked in both get-ups, I can testify that the farmers knew what they were doing.  For instance, we had one of the hottest summers on record in 2012 when the daytime highs were in the 100s for dozens of days, sometimes as high as 112 degrees.  I worked at least 8 hours a day tearing down a two story house and, if you have ever done deconstruction, you know the work is much more strenuous than most phases of construction.  I am convinced that I could never have done as much in shorts and tees due to something called evaporative cooling.

Evaporative Cooling

I have worked in "farmer attire"  -- bib overalls, long sleeve shirts and a floppy broad brimmed hat for most of my adult life.  When I hear it from my younger friends for being old-fashion, I explain the advantage my arrangement has over their flimsy clothing or bare skin in terms of evaporative cooling.  Once my clothing is ringing wet with sweat, it has a cooling effect that is not possible with thinner clothing where perspiration evaporates too rapidly for effective cooling; bare skin is even worse. The bibs on the overalls add an extra layer that helps to cool the chest.   When I come in for lunch, I change to dry clothing while inside but switch back to the wet clothing before going back out so as to benefit immediately from evaporative cooling rather than suffering from the heat while waiting for dry clothes become saturated.

Carhartt Overalls

The Carhartt overalls have some advantages over the denim "farmer type" bibs and definitely over typical pants like jeans in that the "pants" part of the bibs are held up by the shoulders.  Therefore, not only do the pants never slip down or the shirt tail rise, there is no uncomfortable pants belt pressing into the skin when overlaid by a carpenter's tool belt.  

The Carhartt bibs have other unique features that bear mentioning, aside from the fact that their duck material is tougher

and wears better than garments made from denim.  The buckles on the shoulder straps lie flat whereas most other bibs have protruding knobs on the bibs that engage the hooks on the straps.  Many of us like to wear wide suspenders on our carpenter's belt to shift the weight of the tools and fasteners in and on the belt away from the waist and onto the shoulders.  The suspenders lie on top of the shoulder straps of the overalls and press the bulky fasteners on most overalls into the skin whereas the flat fasteners on the Carhartts are comfortable under the suspenders. Unfortunately, the knobby fasteners that close the gaps of the sides at the waist are often uncomfortable when pressed into the flesh by the carpenter's belt laden with heavy tools.   Seems to me that flat fasteners of some sort instead of knobs at the waist would improve the Carhartts even more. 

Knee Pads

Another advantage to Carhartts is that they have built-in compartments in the legs for after-market knee pads that are quite effective for working on hands and knees.  They are not bulky enough for serious hands and knees work like laying flooring but are thick enough to save the knees during other kinds of construction work.  And they sure beat shorts and bare knees!

The pads are available online at www.softknees.com or 888-4KNEEPAD for nominal cost.  The openings to the knee pad pouches in the Carhartts are at the bottom.  The pads are rolled tightly and slipped through the openings.  When a pad clears an opening, it springs open and lies flat.  They cannot easily be removed even for laundering but, when the overalls wear out, the pouches can be cut open and pads moved to another pair of Carhartts.  I work with three pairs of pads and none have shown any wear after use in several pairs of bibs each over quite a few years.