If you saw smoke coming from the wall, you’d call the fire department and evacuate the house.

If you saw smoke coming from the wall, you’d call the fire department and evacuate the house. So why, when you see water dripping from the ceiling, do you put a bucket under it, and let it destroy your home just as surely as the fire would, just more slowly?

This is just a quick thought for the day. Water can be extremely damaging, but it seems so innocuous that people often ignore it until it destroys their home or their family’s health. Take every drip seriously – imagine that each drip is a puff of smoke coming from a hidden fire.

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.

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.

How Can Your Bath Fan Cost You $20,000?

Bath fan venting ino the atticAn improperly vented bath fan can lead to tens of thousands of dollars of damage to your home and even create a health risk. How? *Moisture!*

The main purpose of a bath fan is to remove moisture from the bathroom after you take a shower. The reason you want to do that is that all that excess moisture can lead to mold and potentially cause your paint to peel and may even rot out your walls. So why do people dump all that water into the attic? Basically, because they’re too stupid and lazy to vent it properly – straight up and out through the roof.

How bad can it really be? Bad! I have had many clients with moldy attics due to this improper fan venting. But one in particular stands out in my mind. It was a beautiful custom home – no expense was spared. I was called in due to mold in the attic. Usually, this means a little patch of black on the roof plywood. But when I opened the door to this attic, I was greeted by a roof covered with fuzzy mold. Everything was damp. This was a problem!

After searching, I found the culprit – the builder had routed the bath fan duct under the fiberglass insulation over towards the soffit (the overhang where the roof meets the house). Often this are has a little bit of ventilation, so many lazy builders run bath fans to this area. However, in this case, there wasn’t even any ventilation slots in the soffit, so the bath fan was just dumping all the moisture straight into the fiberglass insulation.

The homeowners had to spend thousands on mold remediation. They then decided to re-insulate the entire area using spray foam and had to pay to get added attic ventilation to avoid this problem in the future. All because the builder was too cheap and lazy to add a $25 roof vent cap and run the bath fan to it.

Broan roof vent cap

So if you ever consider venting a bath fan into the attic, remember this story. Always vent bath fans straight up and through the roof. Use insulated ductwork from the fan to minimize the chance of condensation in the duct. And use a high quality roof cap, like this one from Broan.

Why not vent out the soffit?

I’ve had some builders argue with me, saying that it’s ok to vent out the soffit. They claim it’s safer because you don’t want to put more holes in the roof because of the risk of leaks.

First off, a high quality, self flashing roof cap like the Broan shown here is very easy to install water-tight. I did two myself and I’m an engineer, not a builder. So scratch that argument – it’s bogus.

Next, think for a moment. What does warm, moist air do? It floats up! Duh. So if you try to vent a bath fan out the soffit, that warm moist air is just going to rise back up through the soffit and back into the attic. It’s hardly better than venting straight into the attic. So under no circumstances should you accept soffit venting of a bath fan. Save $50 on installation today, pay thousands for mold remediation and a new roof tomorrow!

The only acceptable alternative to roof venting is sidewall venting. You might do this when you have a slate roof. In this case, you can route the vent to the nearest exterior sidewall. it’s not perfect, but it will do if it’s not too far away.