You need a schematic detail and a useful work specification in your next Contract

Whenever you hire someone to work for you, you need to have a complete understanding of the work specifications. This often gets overlooked in the happy talk and the verbal promises made and you then end up with what actually what is included in the signed agreement.

Proper specifications are essential as to what quality trade practices demand; and help you make sure that is what you are getting. There are things you might feel are too trivial for this, and that is your decision; but a written spec adds clarity, alleviates unrealistic expectations, and certainly helps with verification. Of course, this is just one key step in finding the right contractor. We discuss selecting contractors here.

Even simple projects like adding a new entry door, replacing windows- there is a manufacturer’s specification that comes with it. You need to include these in the contract, you need to understand them, and you need a method of verification that the installation specs were met.

The conscientious contractor will be happy to oblige. They like it when home owners call out skill and details rather than a fixation on lowest price. They are proud of their skills and customer care. It is too bad, but caring about customers is not as commonplace as you might think- I am talking about actions here, not happy talk. Actions speak louder than words when you pay attention.

When you address work specifications, you are underlining that you care and are aware.

Keeping leaks out of windows have become such a problem in the last decade or so, that building standards have really ramped up to keep water out of walls. Engineered wood is loved by mold, and mold finds a wet leaky section of wall a lovely place to grow. We go into exceptional detail on openings in the walls here.

The water control layer in your home is a perfect example of the necessity of work specifications. There is an exact spec for sloped roofs and for every type of protrusion through your roof and a detail for every transition to siding or roof ending. You can check out roofing details here as an example.

Roofs do not leak that are built to the specifications of the National Roofing Contractors association or our own local branch- the North Texas Roofing Contractors Association or the specifications of the Asphalt Roofing Manufacturers Association. The trouble starts when the contractor you hire makes their own rules and sets their own standards. We discuss roofing in much greater detail here.

Sidewalls in Texas also have problems with leaking and creating mold in walls. The design of the water shedding layers on a wall is called the drainage plane. We discuss the drainage plane again when we are talking about the ways water gets into your home structure.  When stuff gets done for expediency and convenience and speed vs. the long term reliability of your home; problems occur.

Problems happen because someone is working without a specification or not being held to the specification. Bad stuff happens more often when people get in a hurry and are not held acountable for the quality of their work.

Your level of concern and your degree of pickiness, of course, will relate to the degree of risk involved- putting brick borders around the oak tree incorporates less risk than brick repairs in a sidewall of your home… and this matters. This is your choice, but accurate building specifications, understood by you, with a plan in place to verify; will give you fewer headaches and not hurt the feelings of the quality contractor at all. In fact, he or she will be pleased that you care and that you noticed.

The quality of the work that gets done depends on whom you hire. We discuss a to-do list before hiring a contractor or remodel here.

Have a question or a comment? Add it below.

Posted in Finding Quality Service People, Home Structural Issues, roofing Tagged with:

Some basic Roofing Mistakes to Avoid

There are several routine crimes committed against roofs out of expediency that should never be done. They do get done, because a homeowner wants to believe a fantasy, and a contractor is willing to do something mediocre just to get the job. So don’t do these.

Existing roofing should never be covered over in a reroofing situation.

You see this done with asphalt shingles to ostensibly save a few bucks now and then, but it is against code, it covers up potential problems with the decking and the roof just does not last as well.

Critical flashing areas can just be nailed over rather than properly flashed with proper flashing metals. A chimney flashing will be much worse off after a recover than with the original roof. The valley flashing on a chimney is a critical point of risk and adding a recover here is at least doubling your chances of really serious problems right from day one of a recover.

Asphalt shingles work really well when it  is well supported against a solid  flat deck.  Recovering over the existing levels the new shingles poorly supported over the roiled surface of the existing shingles.

The recover can trap moisture, cause the new materials not to lay properly and, if push comes to shove, you basically have no warranty.

We also have to be very sensitive to slope.

Any slope flatter the 3:12 which means a 3 foot elevation gain for every 12 feet of surface run… is the flattest slope that works with the standard spec for sloped roofing. You see roofers on occasion flirting with low slopes. Maybe it is s remodel, and the roofer is a roofer in name only, but you see people putting on roofing and adding an extra layer of underlayment, maybe, to help keep water out.

Once upon a time there were roofing specifications for low slope roofing that called for a double layer of underlayment.  But you don’t want this. If you get into a low slope situation, you want a waterproof specification just like for a flat roof.  With a low slope spec, you are hoping the water runs off before the water soaks through. Particularly, if you have a lot a long slope to drain, makes the situation even worse.

There are new self sticking membranes used in sensitive areas of the roofing that reseal themselves around nailheads, but this is not as good as using a roofing spec designed to keep out water.

Your good old standard roof spec can run into low slope situations as part of the roof slope configuration. Different slopes can be tricky, particularly in a situation where a roofer is moving at high speed; say, new construction. Make sure you also see the discussion on getting the roofing details right.

You might want to check out the page on the problem home.  If you have a chronic problem and the contractor is making excuses, then you might have a problem home with unique little structural traps build right in. Check out the at risk  home here.

What did I miss? 

Do you have a question or a comment; feel free to speak up. What you say might help someone make a better decision.


Posted in roofing

Climate Zone Information for North Texas

This website discusses home comfort issues as they relate to Texans living in North Texas. See the map below for a general geographic grounding. We are discussing zone 3 on this website. This climate zone is considered warm and mild in nature. Weather on any day can get wild, but on the average, our zone is described as warm and mild.

It is essential you know and understand your climate zone and the implications it has on your comfort level and the ability of your home to keep you comfortable without wasting energy.  A critical attribute of zone 3 is high humidity. Now, South Texas is much more humid, but we are impacted by humidity here in North Texas. More on this below. And North Texas is a cooling dominated climate. We spend more energy for cooling than heating. More on that later.

Here is a climate zone map of  North Texas from the 2009 IECC – International Energy Conservation Code. Cities and zone information have been added for orientation.

It is important to know, if you are visiting outside this zone, the information on this website might not be appropriate for you. Also, be careful at other websites. Make sure what you are reading makes sense to you where you live. You can find helpful information at the IECC site

Here in the United States we have huge variation in climates. We can’t get much colder than an iceberg called Minnesota. It doesn’t get much more balmy than South Texas, Southern California and South Florida. Here is Texas we can live in any of 5 climate variations. Therefore each zone has climate characteristics that must be addressed. In the south it is hot humid conditions. In the North, the big issue is nasty cold weather.

The climate you live in impacts the challenges you face to protect your home and save energy. Your climate determines  how big a moisture problem you have, how big an energy challenge you have during a heating season and/or a cooling season.

Your latitude relates to length of daylight and the inclination of the sun over the year. The location of the sun and your own solar orientation in your home and window layout impacts the solar loading of your home and your comfort level and should impact home design.

The critical issues that make a difference here are based on temperature and average humidity.

A little orientation-  an energy load for a particular climate is rated in heating degree days and cooling degree days.

The daily average temp is taken from the high temp and low temp, then averaged. That number is subtracted from 65 degrees – the chosen temperature of comparison- and that number is the degree day. If the average temperature is hotter than 65 that number is added to the list of Cooling Degree Days, and if the daily average temperature is below 65 degrees it is added to the heating degree days.

Ten days of daily average temperature of 40 degrees would give you (65-40) x 10 or 250 HDD – heating degree days. The CDD is similar but would be calculated on the temperature above 65 degrees.

Humidity needs special attention here.

Here in North Texas, we are in a cooling dominant climate- which probably does not surprise you. Humidity is another big factor to take into account in North Texas Here is a chart of average low and high relative humidity taken from average data from the DFW Airport weather reporting station over the last several years.


The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

The daily average low (blue) and high (red) dew point with percentile bands (inner band from 25th to 75th percentile, outer band from 10th to 90th percentile).

I swiped this great humidity map from  This implications of high humidity are huge. How well your home- your structure and your mechanical systems handle moisture dictates how healthy your indoor air is- how comfortable you are in your home and contributes to musty smells. You can gain a valuable perspective on moisture and humidity and dewpoint here.

Your home is unique. It is essential that changes you plan for your home reflect the climate we have in North Texas, the solar issues we face, and that solutions offered to you address these given conditions.

Beware of canned solutions and magical products. We discuss this issue here. 

Any questions or thoughts?  Add your comment below.

Posted in energy saving strategies, Moisture and humidity Issues

We can Learn a Valuable Lesson from a Simple Supply Register

HVAC supply grill

A standard HVAC supply register or grill or cover… . What do you call them?

You have probably seen these before. Look up at the ceiling and you will see these. You know them as HVAC supply system register sor as a supply grill. There are two pictures here because this one has a problem it is loose and the foam gasket has pushed the register away from a tight fit with the sheetrock. This gap makes a nice hole for your conditioned air to leak out of the house.

HVAC supply grill not fitted properly. Gasket has pushed open a gap

This supply register has a problem. It does not make a well sealed connection to the opening in the sheetrock. This provides an air leak passage.

Now this grill here is on a side wall so air leaks here would be escaping into the stud wall and out into the attic space through joints between studs and the top plate. You pay for all that conditioned air you are heating in the winter months that heated air is floating up and floating out into your attic.

Then in the cooling season, you don’t really want all that hot humid  air drifting in  through the ceiling in the summer as your cool air leaks out around the sills and the lower reaches of your home. Your conditioned cooled air leaking out at the slab level of the house creates the low pressure at the ceiling level. Air leakage requires a pressure differential and pathways to actually leak, and we don’t want any extra pathways for air leaks.

This needs to be repaired. This screw needs to be resized or something inserted here to allow this screw to regain a  purchase on the fastener receptacle of the register.

Now you might wonder why this issue  ends up being talked about on an air conditioning site. Well, the world has changed and the proper performance of mechanical systems are totally intertwined with the structural components of your home that keep out air leaks and insulate your home. even solar loading is involved, how much direct  sunlight comes into your home during the summer and during the winter and what times of the day…

All of these structural issues are part of modern design of HVAC systems which call for load modeling for your home to insure that equipment installed properly matches what your home needs for maximum comfort.

Seeing homes as a system and understanding the critical interdependencies between mechanical systems and the physical structure are keys to maximizing your comfort at the best investment in energy. This concept of understanding and making design recommendations through this prism is called home performance and smart HVAC service companies  are on the forefront of making sure their customers and their pre-customers are kept abreast of the information they need, to insure they are breathing healthy air in their homes, and are comfortable.

And as building science has proved and as the concept of home performance dictates, they look at your home as a working system not just a series of mechanical devices and ducts that distribute air.

If you have any questions about air leaks and home performance and the comfort and safety of your home, ask your chosen HVAC company. If they are happy to  discuss this, well you have probably chosen well. If they  poo poo design and start to proscribe solutions by pieces of equipment; well, keep looking. You need a progressive HVAC company following the new design tenants of home performance recommended by the ACCA – the  Air Conditioning Contractors  of America.


Posted in HVAC - Heating and Cooling

Is this Gap typical of your return air duct system?

Air gap under door in the functional return air system.

This is a gap under a bedroom door. It functions as the return air ducting. When your supply ducts deliver cooling air to your private space, the air returns to the central air conditioning unit through the return air system. This gap is that system in this particular dwelling. This small gap creates back pressure that will cripple the systems ability to circulate air. 

Yes, this is a silly picture. Almost impossible to make out what it is supposed to be. Yet the subject here is really important to the fundamental performance of your HVAC system in your home.

This is , functionally, a return air duct. Well, not really a duct but this crack under the door is the space for return air that has been delivered to the supply registers in the living space behind this door.

We are talking here about a central air distributed system, and behind this door are an assortment of registers supplying heated air or cooled air to the  bedroom and the bathroom behind this door.

So why all the fuss about the crack under the door?

Proper sizing of cold air returns is a fundamental issue in mechanical systems that work properly. This small crack cannot move the amount of air that the system wants to deliver through the supply ducts. For every cubic foot of air supplied, the same amount, over the same time frame, must be returned to the central system. Thus, constricted  return ducts can cripple air flow. This simple fundamental problem could be the source of air balancing issues, and comfort issues in this living space which are causing discomfort and disruption in the whole house depending on who is trying to live behind this door.

There are several important takeaways here. Let’s enumerate them.

  1. Unless this fundamental issue is addressed, these rooms will not be comfortable. You can replace air handlers, go bigger, go higher performance; but until the fundamental issue is solved, this room will not be comfortable, and the system will not work as efficiently as expected.
  1. You also need to understand that placing anything over this crack- a rug or a towel, to keep out noise, or keep out prowlers; well, the heating and air conditioning system will suffer with even worse performance.
  1. Now, depending on who lives and spends time behind this door, the whole house could be disrupted by the level of discomfort which occurs here. Someone in a better functioning part of the system could be overcooled or overheating- of course, depending on the season; if the person who runs the thermostat lives behind a portion of the house not well served by conditioned air.
  1. And we all want healthy indoor air. Healthy indoor air is, in large part is a function of the level of humidity in the home. High levels of humidity help dust mites flourish, and mold and mildew flourish. These biologicals cause throat  irritation, and sinus problems, and scratchy eyes; and keep people awake and miserable, and actually make people sick. And any portion of the house where the HVAC system is stressed high humidity with be present and these conditions can flourish.

How would such a system be built in the first place?

You might wonder why such a silly system was ever built; and, really, you know the answer. It was cheaper to build. What more can be said, except that you the homeowner are put between the rock of cheap construction and the hard place of discomfort in your home.

You do not have to put up with discomfort. There is a fundamental cause, you just need to make sure the company you call takes the time, to carefully listen to you, and patiently asks you a lot of questions that can help pinpoint these kinds of questions. You want a company that expands  their  study and understanding of your home beyond just solving problems by selling components in the mechanical system.

You need a company that

  • has years of experience actually solving HVAC problems
  • has the breadth of expertise to deal with all aspects of home performance
  • and has a dedication to customer comfort and is in the business for the long haul, which means caring properly for customers now to have them as customers in the future.

Now this is harder than you think. Most work on HVAC systems occur when the temperature is the coldest or the hottest because that is when systems are under strain and breaking down.

Well this is also when HVAC service companies are under strain and, while under strain, many companies can become expedient- to getting in and getting out, and making the sales and moving on;  and precipitous actions can take place, when less than thought out solutions can be offered- because of the strain.

Make sure you call a company that has the right combination of skilled people and dedication to  customer care. And make sure you are patient with them because they probably do not sound like the HVAC sales people you have talked to before. It takes extra time to actually diagnose fundamental issues and get beyond the old style of rules of thumb which allowed such fundamental flaws to continue until now.

Look around your house and consider the following.

Does your system have mechanisms for the return air in your home that do more than expect air to crawl through cracks under doors?

Do you notice any differences in the airflow in your home from room to room? There are many reasons why air systems do not work evenly across a home and you do not have to put up with this.

Do you have questions and concerns about how air seems to circulate in your home?

Do you have an HVAC service company that you trust? Ask them to help diagnose your comfort problem and just see how thorough they are. If they don’t get beyond the recommendation of new equipment, well, you need to look around for a more comprehensive company.  There is never a better time to prevent or solve a comfort problem than acting right now. And the first step is finding a company that can actually help you.


Posted in HVAC - Heating and Cooling
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