There’s No Such Thing as a Small Leak!

Writing these posts have reminded me of all the horrors I’ve seen in buildings and homes. Unfortunately, some have been in my own house! This is one of those (unfortunate) cases.

This all happened some years before I got into the building science business, so I didn’t know the warning signs to look for, and it cost me dearly!

Not long after I moved into my home, we started hearing loud “settling cracks” coming from our kitchen, which has an attached sunroom. For a long time, we didn’t think much of it. The house was built in 1957 and had gone through various renovations before we moved in, so we just attributed it to natural 

Then strange things started happening. A large crack appeared in one section of the wall and floor tiles in the sunroom were breaking. However, this time, we attributed it to poor installation. Contractors echoed this sentiment, so we let it go.

Finally, in the middle of winter, after a particularly loud *CRACK* coming from the kitchen, I went to explore. It was then I noticed a blackening on the wall behind the kitchen table. I thought “mold”, and went to explore. Like any guy, I poked at it with my finger. Unfortunately, my finger went right through the wall! This was the start of a long night…

As I continued to poke at the wall, I discovered that the entire short wall, on which the prefab sunroom was installed, was rotten. This must have been going on for years because almost all the 2×4 wall studs had turned to mud – completely rotten. Argh!

By the end of the night, I had removed most of the floor tiles and all the rotten wall parts and found pressure-treated lumber to support the sunroom. Frankly, I was surprised that the entire sunroom hadn’t fallen down – it was that bad.

So What Happened?

What I discovered during the deconstruction was that all the materials were wet. This included the exterior walls and the subfloor under the tiles, which by now had rotted out too.

The following day, after I’d warned my wife not to set foot in the sunroom and start getting bids on rebuilding the kitchen, I went outside and studied the stone wall on which the sunroom was built. I also looked from the inside to see if I could find the source of the water. In fact, it was quite easy to find – I could see daylight through the wall! Further inspection showed that the builders were depending on caulk to water-seal the structure. This is a common cause of leaks.

Sidebar – Rant about Caulk

Folks, caulk is never to be used, especially on the outside of a house, as the primary line of defense against water leaks. If you use caulk, it will eventually give way and lead to a leak. I guarantee this. No matter what any contractor, brother-in-law or best buddy tells you. Caulk should not be used this way.

Think about it. You’ve got two different materials – in my case, an aluminum sunroom sitting on a stone wall. The massive stone wall changes size very little as it warms and cools while the aluminum changes dimensions considerably. In technical terms, the “coefficient of linear expansion” of aluminum is high compared to that of sandstone. If you want numbers, it’s double. And caulk? That expands and contracts ten times as much as metal and stone!

What that means is that if you go from 0F in the winter, to 100F in the summer (higher if the sun is shining on it), over the 8ft length of the sunroom, the aluminum will expand between one and two millimeters more than the stone and the caulk wants to change length by about an inch. If this happens repeatedly, and you combine these forces with the shrinkage of the caulk over time, the result is a guaranteed leak.

So if you’re considering using caulk in this way – don’t do it. Fixing the damaged caused by that $3.49 tube of caulk will cost you tens of thousands of dollars. 

Back to the Leak…

What else did the builder do wrong? Well, they ignored a piece of information that any grade-schooler could tell you – water runs down hill and puddles on flat spots. Why do builders think that they can ignore the laws of physics?

In this case, they built the sunroom on a flat topped stone wall. So when it snowed or rained, the water would sit on the wall – the only water barrier being a little bead of caulk. Not to mention that SANDSTONE IS WATER PERMEABLE, so any water that sits on it can wick around the caulk and enter the house.

The solution is relatively simple. Slope the top surface so that water flows away from the house – yes folks, water runs down hill. Use this to your advantage.

There’s No Such Thing as a Small Leak

This leak, caused by poor design and improper use of caulk, went unnoticed for a decade until my sunroom almost fell down. I won’t tell you how much it cost to fix it right. But it was such a painful learning experience. In fact, I’m here writing this today largely because of what I learned. Unfortunately, one of the most important things I learned is that some builders ignore the science of building and instead just focus on cosmetics. Remember, you cannot win the fight against physics!

What other problems can arise due to “small” leaks? Well, have you ever had a slow drip somewhere that you didn’t fix? You know, one of those leaks that maybe you just put a bucket underneath so that it wouldn’t stain your carpet?

Well, if you did that, you risked having your house collapse. Maybe not all at once, but it starts with a slow drip. Who knows where the drip started. Perhaps it was running down from the roof, working its way down a rafter, dripping on the attic floor, migrating down a wall, puddling on the ceiling, then finally dripping on your floor.

Every area that is subject to repeated wetting like this might, over time, get moldy then get eaten by termites or mold-related products. I’ve seen support timbers that became so soft I could poke my finger through them. Do you want this holding up your house? What happens during the next big snowfall or wind storm that puts pressure on your home? Seriously – this is life threatening stuff!

So if you ever discover a “small” leak, don’t wait till next month, or next year to have it fixed. Immediately, try to find the source of the leak. If it’s a leaky pipe, shut off the water to that pipe and have it fixed. If it’s a leaky roof, get it fixed correctly. Whatever the case, you need to dry out all the building materials, preferably with fans and dehumidifiers, as soon as you can, and get a professional in there to fix it.

A note about mold: some people have sensitivities to mold, others don’t. If you have moldy conditions, you have to deal with the source of the water, or the mold will keep coming back. But whatever you do, if you have any concerns, call in a mold remediation specialist. I can’t stress this enough – a specialist! Not your buddy who does carpentry on the side. Probably not your builder. A specialist who knows how to safely get rid of the mold and prevent it from coming back.

Got Mold?

If you’ve ever owned a home, you’ve probably had mold at some point. Mold on the wall. Mold in the shower. Mold in the basement. Maybe mold in the attic, like shown in this picture.

Mold spores are all around, floating in the air, on surfaces, in your house plants, wherever you look, you’ll find mold spores. This is perfectly natural!

On the other hand, when mold grows uncontrollably, like shown above, it can cause horrible damage and have serious health ramifications if you have sensitivities.

So what causes mold to go from benign to growing like crazy? 

The answer lies in humidity. Mold needs moisture in which to grow. That’s why you often find mold in showers and basement. But not just any moisture, but high levels of moisture. “Ok,” you say, I understand showers and basements. “I can run the bath fan for a while after a shower and flush out the humidity” (yes, you should run the bath fan for about 20 minutes after a shower!) “And I put a dehumidifier in the basement to help that problem. But what about the darned attic?

Let me tell you about attics! But first, I have to tell you about condensation…this won’t be painful, I promise.

What is condensation? It’s simple! – it’s just the water vapor in the air finding a something cool enough to for the water vapor to turn into liquid water. Warm air can hold more water vapor that cold air. That’s why the window in the bathroom gets covered with condensation when you take a shower. The air in the shower is hot, and saturated with water vapor. Everything else in the bathroom is cooler, but the window (in the winter), that’s really cold. So that’s where you see the condensation. 

“Ok”, you ask, “but what about the attic!?” 

Here’s the deal. During the winter, do you heat your attic? Hopefully not. There’s probably a lot of insulation on the attic floor, trying to keep the heat in the house and the attic cold. Aha! The attic is cold! And what about the roof? It’s really cold, especially on the north side of the house which doesn’t get any sun.

So, any moisture that gets into the attic is going to condense on one of these cold surfaces. Where the moisture condenses is a big clue as to where the moisture is coming from.

For example, in the picture at the top of this post, it’s immediately obvious that the moisture is coming up that roof cavity and condensing on the cold roof in the attic. In fact, that wood is saturated with water – literally dripping! That means there’s a lot of moisture coming up that cavity.

How’s that happening? Well, I can tell you with 100% certainty that the moisture is NOT coming from the outside. Why? Because the outside air is cold and dry. If it were going to condense, it would have condensed outside, not on your roof. So rule that out.

If not from the outside, it must be coming from the inside. AHA! Remember, warm air holds much more moisture than cold air and inside the house, there are showers, animals, cooking, breathing, house plants and so on. All putting moisture in the air. That moisture rises up through the house and follows the ceiling upwards. And what’s above the ceiling? The attic. 

But how does that moisture get into the attic? You’ve got walls and ceilings and sheetrock. What gives?

Water is a tiny, tiny molecule. When in its vapor form, it’s still tiny – vastly smaller than liquid water. Think about a balloon. Even the tiniest hole and the air comes rushing out. It’s the same with your house. That recessed light you installed? That’s filled with holes. Ceiling Fan? Holes! Electrical outlets? Holes! Door frames? Holes. 

There are holes everywhere!!! And any moisture in your home is going to find those holes. In fact, during the winter, literally gallons of water is moving from the inside of your house into these cavities – walls, attics, etc.

In small quantities, the moisture harmlessly flushes out and is dried out by the winter air. No problem. But get a big enough hole, like around recessed lights, and you’re fighting a losing battle. Seriously. Recessed lights are one of the biggest problems I encounter because they’re never installed air-tight. NEVER.

And so, almost every roof that I look at that is near recessed lights, is covered with mold. There’s probably millions of dollars of rotten roofs caused by recessed lights. This is made worse by the stupid practice of installing ridge vents on homes in an attempt to add ventilation. 

This is a controversial statement, so let me explain further. What’s the purpose of a ridge vent? It’s to give air a place to rise up and out of the attic. Well, if air is leaving the attic, where does it come from?

In many cases, there’s no place in the attic for air to come in and replace the air that’s going out the ridge vent. So what happens? That ridge vent sucks the air out of the house – exactly what you do not want to happen!!! So the better the ridge vent is working, the more moisture is getting sucked from your house into the attic and the more mold problems you’ll get. This is why so many contractors actually make attic mold problems worse. They’re just solving the problem the way they were taught – add more ventilation!

The Solution

Before you panic, there are solutions.

First, remember, moisture problems and mold occurs where warm moist air comes in contact with cooler surfaces. So how do you avoid the problems?

  1. Don’t let warm, moist air out of the house
  2. Don’t let warm, moist air touch cold surfaces
  3. If warm, moist air does get into a cold space, get it out of there fast.

Got that? It’s that simple. If you follow these rules, you cannot have moisture and mold problems.

So how do you do this?

  1. If you don’t have recessed lights, don’t add them! 
  2. If you already have recessed lights, seal them airtight. This requires some handy-work. Seal the circle around the perimeter between the light fixture and the ceiling. This can be done with spackle and high temperature silicone caulk. All the holes in the fixture? A dab of caulk or some foil tape can largely seal those.
  3. If you have other holes in your ceiling, seal them up the same way. Pretend you’re building a submarine. Seal all the holes like your life depends on it. Read this article on cathedral ceilings.
  4. If you’re building a house and you want cathedral ceilings, read this article. Then have at least 4” of closed cell spray foam applied directly to the underside of your roof. You’ll be shocked at the price, but consider this – if you use fiberglass and your roof rots out, you’ll spend at least $10,000 to redo your roof. Spray foam will seem cheap in comparison.
  5. If you’re ventilating your attic, do NOT just add a ridge vent. You have to install a ridge vent AND matching soffit vents. Or, do it the old fashioned way, and install gable vents on each end of the attic so that the air can flow through. You can’t just have one vent. Air has to flow in and it has to flow out.

When you’re all done absorbing this, read my other articles. This is probably the most far reaching and potentially complicated topic I’ll write about, so there’s lots of material!

Basement insulation and moisture

Bathroom venting

Cathedral ceilings

Good luck!

Ducts – How bad are a few leaks?

Air return duct - wide open

Let me give you a hint – leaky ducts can kill you.

No joke. Duct leaks are serious business, and yet, most people have no idea just how important ducts are. I’ve had arguments with HVAC contractors over poor duct installation practices. Frankly, it’s criminal when ducts are installed like they are in the picture above. I mean, what were they thinking?

Ok, let’s take a step back. What is the purpose of ducts? They’re there to move air around your house – distributing heating and cooling as uniformly as possible to keep your house comfortable. Most homes have two types of ducts – supply and return

Supply Ducts

The purpose of supply ducts is to supply conditioned (heated or cooled) air to various rooms in the house. Each room has specific requirements, so proper duct design is a science. How big is the room? Does the room get a lot of sun or is it shaded? Is it upstairs or down? Does it have lots of windows? How much insulation does it have in the ceiling and walls? How far is the room from the furnace?

All of these factors affect the supply duct design. Unfortunately, most installers take a “cookie-cutter” approach, and just put one or two supply registers in per room and call it a day. If you’re lucky, they’ve installed dampers so that they can adjust how much air gets to each room.

Assume that they do all these things right. What happens when the ducts are leaky? Now all the calculations go out the window because the needed air isn’t reaching each room. In extreme situations, I’ve seen rooms receiving *no* air! Often this occurs when the ducts run through the attic and one has become detached. So now, all the air that’s supposed to be supplying heat to a room is spewing into the attic. How much do you think that costs you in wasted energy?

Return Ducts

Return ducts are used to “return” air back to the furnace or air conditioner. Think about it for a second – every room should have a balanced air supply, with the same amount leaving as is entering. Otherwise, it’s like blowing up a balloon. If the door is closed, the system is trying to blow air into a closed space. What happens then? The excess air tries to make its way out. Sometimes it will go out into the hallway and makes its way back. Other times, it leaks outside, so again, you’re wasting energy.

Think about what happens when the return duct leaks in the attic. Any leak in the attic sucks air into the ducts from that nasty space, usually filled with dust, mouse droppings, and fiberglass, as well as the obvious outside air that might be cold or very hot. So, return air leaks are bad, really bad. They’re unhealthy and really hurt your energy efficiency. How much? The example shown above where the filter port is open will decrease the system efficiency 30%-50%!

Now, what happens if you have a duct leak in the basement, like shown at the top of this article?

Well, first off, the room upstairs that’s supposed to have a working air return doesn’t, so the air flow won’t be proper. That’s the good news. The bad news is that a return air leak this big can suck the air out of the basement, creating a low pressure zone in the house. So low that it can literally suck the exhaust fumes out of the furnace or water heater or make it malfunction so that it generates carbon monoxide. In fact, it can kill you. 

This problem is so serious that the Building Performance Institute (BPI) requires all certified energy auditors to test for these potentially lethal conditions. And remember, you might have several things working to create dangerous conditions – the leaky return ducts, the clothes dryer (which might be expelling large amounts of air from the basement), the furnace (which also uses air for combustion), and the water heater. There are also natural forces at work that make basements lower pressure.

So when an installer takes shortcuts and doesn’t seal your ducts air-tight, not only are they robbing you and maybe making you sick, they could kill you. If you’re having duct work done, or a new house or addition built, insist on having the ducts tested. I will cost several hundred dollars more, but what price do you put on your family’s life? Don’t take shortcuts – make sure it’s done right.

Want some duct fixing supplies? I’ve put together the best items for this on an Amazon store. Check it out and support this site. 

Dam ice Dams

Link: Dam ice Dams

Want to learn the “building science” of ice dams? Building Science corp has an amazing set of notes on building problems and precautions. I consider them the source for building information relating to tricky issues that tend to foil most contractors.

High Electric Bills, Wasted Energy & Central Humidifiers

It’s winter, and for many people, that means dry skin, cracked lips and nosebleeds, so I’m often asked about whole-house humidifiers – humidification systems that connect to your central heating system to distribute moisture throughout the house.

As noted in another post, I’m not a big fan of these units. Any time you concentrate humidity, you run the risk of growing mold. A little leak in your duct system and you could be squirting moisture into walls, ceiling cavities or other areas where you might not know there’s a problem until the entire thing rots out.

It is vastly preferable to use standalone units that use cold water, a small fan and a pad to soak the water. These units are very energy efficient. But beware, there are energy hogs among the small units too. some of them have electric heating elements to evaporate the water and use ten times the electricity as the simpler models! 

In spite of my personal aversion to these units, I recently worked with a friend to track down the source of her high electric bills. She’s an engineer too, so she was reading manuals and trying to uncover the problem. 

As it turned out, she told me “Ted – I have a whole house humidifier, could that be an issue? It runs on hot water.” I’ve heard of this before. Units that squirt hot water into the air stream of the heating system. The trouble is, her unit worked very inefficiently, running the hot water the entire time the heating system is on!

Let’s look at this. This system was basically leaving the faucet on for 8-16 hours per day, using 50-100 gallons of hot water just to put a few gallons of moisture into the air. What a horrible waste!

When you run the numbers, you find that, at the low end, this was costing her $30/month to run. However, with high electric rates in the northeast U.S. and cold winter days, this number is about $100/month! 

Fortunately, there are other ways to solve the problem. If you must have a whole-house humidifier, look for one that doesn’t use hot water and doesn’t run the water the entire time your heating system is on. You’ll have to do your homework, and maybe argue with your heating contractor who will just want to install whatever unit they have sitting on their truck. But it’s your utility bill, so don’t settle.

Guidelines for choosing a whole house humidifier:

  • It should run on cold water, not hot water
  • It should only run if the humidity is below the set point
  • It should not run water continuously when the heating system operates

In addition, whole house humidifiers can be breeding grounds for mold, depending upon the design, so make sure you service it regularly. That means draining the unit and opening it up to clean it out as per the manufacturer’s instructions. Off-season (typically Spring, Summer and Fall), they should be disabled, otherwise they work against your air-conditioning system causing it to work extra hard.

So if you have high utility bills this winter, check to see if you’ve got a whole house humidifier. It could be pouring your utility $$$ down the drain!

If you find Ted’s Tips to be useful, please support my work and visit my Amazon store. In it, I’m collecting the products mentioned in these articles so you don’t have to hunt all around the web to find them.

Don’t let your heating system kill you!

Boiler flue disconnected from chimney

In light of the recent tragedy in Allentown Pennsylvania (more or less just down the street from my house), I thought it important to remind my readers of the importance of maintaining their heating systems.

Tragic accidents like this don’t have to happen. But every year, people die in explosions caused by gas or propane leaks or are poisoned by carbon monoxide due to improperly functioning heaters. What can you do to minimize the chance of this happening to you?

  • Inspect your system now, checking for any irregularities
  • Install carbon monoxide detectors throughout your home
  • Have your systems professionally inspected every year
  • If you smell gas, air out your home, evacuate, and call the gas company

Inspect your system

A simple visual inspection will often reveal dangerous problems. Look for anything that doesn’t “look right.” For example, the photo at the top of this page shows the exhaust flue connection to the chimney. Does this look right? This system could easily have been spewing carbon monoxide into the home, making the occupants sick or even killing them. 

Check for any signs of improper installation or operations. Any drips or leaks should be addressed professionally – most homeowners do not have the proper tools or training to safely repair their heating systems. You wouldn’t operate on your child would you? This is no different.

Install carbon monoxide detectors

Any home with combustion devices (gas, propane or oil) should have carbon monoxide detectors on each floor, located as per manufacturers instructions – typically close to the bedrooms. sells a wide variety of detectors, one of them caught my eye because it does more than just sound an alarm – it shows you the CO levels in your home:

Kidde Carbon Monoxide Alarm with Digital Display

This is a very reasonably priced unit, well worth it. 

Keep in mind that most CO detectors/alarms only alert you when the CO levels rise high enough to make you sick. Personally, I’d rather be warned before I’m being poisoned! 

Remember – CO detectors, like smoke detectors, have to be replace about every five years. If you’ve got an old unit, throw it away! The detectors deteriorate over time.

If you smell gas, do something about it!

Frankly, I don’t know why anybody would live in a house that smells of a gas leak. The gas company adds an odor to the gas for a reason, and if it gets strong enough to smell, it’s worth fixing.

Do not listen to a technician who says “it’s nothing to worry about.” This simply means they don’t have the proper tools to find and repair the gas leak. Find another technician, qualified to diagnose and repair leaks, and don’t accept no for an answer.

A professional will have an electronic device that looks like this 

It is capable of detecting minute quantities of gas. They should trace every inch of your gas pipes, especially around connections, until they find the leaks. Once they find the location of the leak, they will spray a soapy solution on the area to verify the leak (leaks will make soap bubbles). After that, they’ll have to disassemble the pipes and redo the connections properly.

Have your systems inspected yearly

Finally, make sure to have your systems inspected every year. This is your family’s life that’s at stake. Hire a reputable heating company and have them do a full test and cleaning on your system every year. It’s not worth waiting until there’s a problem, because by that point, your system could have killed you. A little preventative maintenance goes a long way.

If you find Ted’s Tips to be useful, please support my work and visit my Amazon store. In it, I’m collecting the products mentioned in these articles so you don’t have to hunt all around the web to find them.

Why are my pipes rotting out?

You’re probably wondering why a blog on energy efficiency is writing about rotten pipes. I’ll cover pretty much anything related to things going wrong in a home, so feel free to ask questions!

Pipe corrosion is a real issue. Even long time plumbers can’t seem to get it right. The reason pipes like this corrode is simple – when you connect two different types of metals together, they act like a battery and one side will be sacrificed to the gods of “galvanic corrosion.”

This is a given. It’s physics and chemistry and it happens. So what went wrong in this picture?

The plumber had an issue – they wanted to connect a 3/4” copper pipe to a 1/2” brass pipe. So they reached in their toolbox and pulled out a steel adapter and screwed it in. In the process, they created a battery that started eating away at the steel adapter. Once it reaches this point, that $1.49 adapter now costs you several hundred dollars because the plumber is going to have to cut the pipes apart and find a new way of connecting them. And you know what? They’ll probably do the exact same thing again. It makes my head explode!

Repeat after me – corrosion is not caused by leaks, it’s caused by electrical interactions!

You must never let dissimilar metals come in direct contact with one another! Keep in mind that some are similar enough, like brass and copper. They won’t destroy one another. Steel and iron are basically the same. But copper and steel is a no-no! Stainless steel and copper will also cause problems.

How do you fix this? You buy a $10 piece called a dielectric union. This electrically isolates the two metals, letting you connect them without problems for years.

Rather than duplicate what’s been described hundreds of times around the web, I’ll just point you to a great article on

Feel liberated now. You probably know more than your plumber. And don’t believe it when they try to tell you that they can connect copper and steel. It just ain’t right!