February 2013 – Geeky Girl Engineer

What not to do with drywall

Posted on February 27, 2013 by geek

Geeky Girl Engineer’s Home DIY Tips for Morons

This is freshly installed drywall.

Guest room after drywall and new window

Drywall is that stuff you paint and hang things on. It is also known as gypsum board because the interior of it has gypsum in it. In bathrooms, green board is used because it is moisture resistant, but it is not moisture proof. It is called green board because it is green. Yes, home buildings supplies have very creative names. It is seen below in my guest bathroom as I was tearing it out for renovations.

Downstairs bathroom deconstruction

Drywall is screwed or nailed to studs. It covers up the insulation, studs, wires, pipes, and everything else that goes behind a wall. Fairly simple, right? Evidently not so much for the morons who “renovated” my house at one point before I bought it. Here is the room that is now my guest room when I was tearing things down to renovate.

guest room deconstruction

Look at the wall on the right that still has the drywall. See the brown outline around the door? Here is an up close photo of it.

Guest room deconstruction. Two layers of drywall for unknown reasons.

That outline is due to a second layer of drywall that was unpainted and revealed when the door trim was removed. Here is another look at it.

Guest room deconstruction. Two layers of drywall for unknown reasons.

So let’s just be clear: there is absolutely no point to two layers of drywall on one side of a wall. One layer of drywall is all you need. In fact, if you add a second layer, then the electrical outlets and light switches don’t fit through properly. I have tried to come up with a logical reason for the two layers of drywall. Best I can come up with is that they noticed the mold on the drywall on another wall in the room and assumed it was from moisture from the adjoining bathroom. Therefore they decided to put up a second layer of drywall to stop the moisture. This makes no logical sense, and the drywall wouldn’t stop moisture from coming through the wall. Assuming this is the reason, they entirely missed the reason for the mold anyway. The mold was due to the fact that behind the drywall was furring strips on cinder blocks. The cinder blocks formed the exterior wall. The two exterior walls of this room are underground, hence the cinder blocks, and there was not enough moisture protection to prevent moisture from the ground coming through the cinder blocks which then would gets to the drywall.

However, I really don’t know why they put up a second layer of drywall. The mold is simply a guess. When I tore down both layers of drywall, I didn’t notice anything wrong with the covered layer of drywall that would explain why it was covered. The summary of this is, there is no reason for two layers of drywall. It is a waste of drywall, and it is stupid.

Geeky Girl Engineer’s Home DIY Tips for Morons

Posted on February 24, 2013 by geek

I have been renovating my current house for two years now, and I realized before I bought it that it had been built and originally owned by smart, caring home owners, but it was later owned and “renovated” by morons. Therefore, in order to help and possibly stop morons out there, I have decided to start a new, sporadically reoccurring series of posts called “Geeky Girl Engineer’s (GGE’s) Home DIY Tips for Morons.” First, a few disclaimers though as to why you should either ignore or not ignore anything I write.

I am not a licensed contractor of any type. I am also not a home renovation expert.
I however have owned and renovated three homes. Much of the work I did myself.
I am a licensed professional engineer (PE), but I am by no means selling or marketing my services as a PE. Also, I am an environmental engineer, so I am more knowledgable about wastewater and hazardous waste and not so much about structural engineering such as one needs when designing and sometimes renovating a house. I hired a licensed structural PE to help with a portion of my current house’s renovation because I demolished a structural wall.
As an engineer, I have been known at times, to adhere to the engineer’s adage which is:
1. If it doesn’t move and it’s supposed to, use WD-4.
2. If it moves and it’s not supposed to, use duct tape.
3. If those don’t work, use a hammer to bang the crap out of it. This may not solve the problem, but it will make you feel much better.
4. If all else fails, use C-4.

OK, I totally made up number 4. I have never actually worked with explosives, which is disappointing. Actually, that is not entirely true. I have used picric acid in a dilute solution before to measure creatinine in urine. However it was always in solution and kept in a plastic container and never at risk of exploding.
As a female, unlike some but not all males, I read the directions. I even read the directions when it is something from IKEA and the directions involve a strange cartoon man, and no matter how well you follow the directions, you always have leftover: three screws, four washers, two nuts, and five wooden dowels. No matter if the piece does not involve wood, there will still be wooden dowels included. Also, I now have a fine collection of Allen wrenches.
I know what I can and can’t do. I also know what I shouldn’t do. I know when to call in professionals. As a chemical engineer, I have the book knowledge to design a petroleum refinery, but I don’t have a clue how to change the oil in my car. I leave that to the professionals, who can also recycle the oil. I fully understand fluid dynamics, pipe sizing, friction factors, municipal waster and waster design, etc. However, I still use a professional plumber for tasks larger than changing o-rings or existing faucet heads, etc.
I am a natural blond.

So, while many might be able to learn something from this series of posts, before you attempt any type of home do-it-yourself (DIY) tasks, please try to figure out if you are in fact, a moron. Consider the follow questions:

Has anyone ever told you that you are a future Darwin award winner or that you almost won a Darwin award?
If you have an electric outlet with two holes, but your plug has three prongs, is your solution to cut the third prong off the plug?
Do you believe building codes are silly and not in the least useful?
Have you ever seen something you did or something very similar to something you did on There I Fixed It? Or are you confused as to why some things are on that site because they look perfectly fine to you?
Do you think that when a female is raped, her “body has a way to shut that whole thing down” to avoid getting pregnant?
Have you ever opened a box containing electronics or some other non-food item, found a little packet and thought “oh nice, it came with a snack,” only to be disappointed when it said “don’t eat”?

If you answered yes to any of the above questions, you might be a moron. If you are going to do anything more complicated than changing a light bulb in your home, you might want to consider calling in a professional. Actually, you may want to consider if you are even capable of changing a light bulb. After all, someone had to be the inspiration for all those “how many _____ does it take to change a light bulb” jokes. Please consider carefully. Your future self, and any future owners and occupants of your home will thank you for it.

There is the introduction. Stay tuned for tips based on the incredibly stupid things I have encountered in this house. Contact me if you have questions. Contact me if you have tips or photos of really stupid things done at your house that you would like to share with the morons out there as something not to do. I can promise that if you ask me a question, and I don’t know the answer, I will not make up an answer, but I may be able to refer you to some sites with actual valuable information.

Short Term Radon Test Results

Posted on February 22, 2013 by geek

Previously I wrote that I was testing my house for radon. I got the test results back this week, and the test results came back as an average radon level of 2.9 pCi/L. The good news is this is less than the 4 pCi/L action level. The bad news is this is still elevated above average house level of 1.3 pCi/L. This test involved collecting radon over four days. At work, I am currently working on a project that involves looking at the indoor air variability due to radon or volatile organic compounds intrusion from the soil and groundwater. Thus, I know better than most how variable indoor air concentrations can be. They can vary a lot. Therefore, before deciding what to do, I have considered the following items:

The test was done in winter under proper closed house conditions. Closed house conditions means keeping the doors and windows closed except for normal entering and exiting the house through the doors. This is not an issue in the winter because it is cold. This is also one of the reasons winter is one of the best time to perform the test, but it also means that the test will lead to higher results than if more open house conditions are maintained. When the weather is nice, I like to open the windows and doors, so that would generally mean at least during those times, the radon concentrations in my house should be much lower.
The test was performed over four days. As I stated, indoor air concentrations can vary a lot, and in terms of those fluctuations, four days is relatively short term. Even ignoring the seasonal effect of closed versus open house conditions, the long term average radon conditions could be much higher or lower than 2.9 pCi/L. The reasons are not fully understood, but exterior temperatures and precipitation can affect it. A long term test over several months or even better a year, will give a much better understanding of the average concentration. If the results had been 1.3 pCi/L or less, than given the conditions, I would probably not be at all worried that the long term concentrations would be higher.
The EPA recommends that the test be performed in lowest habitable portion of the house. As such, I placed the test in the guest room for that and other reasons stated previously. However, I am almost never in the guest room. I don’t have guests that often, and the door to that room remains shut most of the time. Thus the only air exchange in the room is via the ventilation ducts and a little underneath the door. Furthermore, my bedroom and all the common areas of the house (kitchen, living room, etc.) where I spend most of my time are upstairs and should have lower radon concentrations than the guest room. Therefore, even if the results from the guest room do accurately represent average radon concentrations, they are borderline for taking mitigation action and probably represent the highest levels in the house. While I don’t want to expose my guests to undue risks, especially since my guests are generally people I like or love, do I want to mitigate based on the results from this room?
Finally, I’m a scientist, and I believe in validation and replication. This was one test result, and home test kits are generally not considered the gold-standard of any type of test. There is no doubt at least of some amount of inaccuracy with it.

Therefore, I have decided to test the house again, but this time for a longer duration. I have also decided to run two tests simultaneously. I plan to place two testers in the house, one in the guest room again and one upstairs in my master bedroom. I have ordered a long term home test kit that can be used to test between 90 and 365 days. I plan to run the test over an entire year to get a much better indication of what the long term average radon concentrations are in the house. Also, by testing both the guest room and master bedroom, I can better understand what my average exposure is both in terms of the average annual concentration and in the rooms where I spend the vast majority of my time. I will also add that while the guest room is a guest room now, as it is bedroom, legally and real estate-wise speaking, and thus in the future it could be a normal bedroom if my life changes or if I sell the house. Therefore I still consider it important to know what the long term radon concentrations are.

Check back in a year, and I will let you know what happened and how I am proceeding.

Testing My House for Radon

Posted on February 16, 2013 by geek

I’m testing my house for radon, and you should also. Winter is the best time to test your house for radon, which is one of the reasons I am testing it now. What is radon, and why am I testing for it? Keep reading.

What is radon? It is an odorless, tasteless, invisible gas that also happens to be radioactive. It is produced naturally from the decay of uranium, which occurs naturally in soil across the United States, and other countries and continents. The United States Geological Survey (USGS) has this neat map showing uranium soil concentrations across the US. Due to its radioactivity, radon is a carcinogen. In fact, it is the second leading cause of lung cancer after smoking. Radon gas is pretty much everywhere, both outdoors and indoors. Like all carcinogens, there is no safe level of exposure. You can’t completely avoid exposure because it is naturally occurring, but it is best to avoid it if you know it is present.

The US EPA estimates that the average home has an indoor radon concentration of 1.3 pCi/L, this means pico Curies, a unit of radioactivity, per liter of air. If your indoor air is above 4 pCi/L, then they recommend you fix your home. I’ll get to what fixing your home means next. Finally if the indoor air concentration is between 2-4 pCi/L, then they recommend you consider fixing the house. It is in that range that the concentration starts to get high enough above background that you might want to take action.

What happens if the radon concentrations in your house are high? First, don’t panic, your house can be mitigated to reduce the radon concentrations. You can hire a professional to install a mitigation system in your house. A mitigation system can either prevent radon gas from entering the house, or it can remove it from the house once it gets in. For example, one type of system sucks or pulls gas from beneath the house and then pipes it safely above the house where it can disperse into the atmosphere. Mitigation systems can be very effective and will greatly reduce your risk of lung cancer due to radon exposure.

Is your house at risk? As shown in the USGS map, some areas have higher concentrations of uranium in the soil than others. Areas with higher soil uranium concentrations will generally lead to higher radon gas concentrations. Also, houses with a crawl space will generally have less radon infiltrating the house than houses built on a slab or with a basement. The crawl space can allow the radon to dissipate before rising into the house. Houses with cracks in their slab are more susceptible because the cracks serve as a pathway for the radon to rise into the house. Also, pipes and conduits such as for wires from the house to ground can also allow radon to enter if they are not properly sealed.

So how do you find out if elevated levels of radon exist in your house? It’s fairly easy. Many states regulate the testing of radon, so you may try contacting your state radon department if it has one. Most of the time, you can go to your local home improvement store and buy a test kit for about $20. That’s what I did. The test kit I bought included two little containers that detect radon. The test kit had certain specific directions for the test containers such as they needed to be at least three feet off the floor, at least three feet from an exterior wall, etc., and they needed to be open for four days. The test containers were supposed to be placed six inches from each other. I presume you get two that are supposed to be placed in the same location for replicability. So here are the high tech test kits.

Both radon detectors placed for testing

Yes that is a tape measure in the photo because it said to place them six inches apart, and I’m an engineer. Now be quiet. The detectors should be placed in one of the lowest habitable rooms of the house. My house is built into a hill such that the front door on the first floor is ground level, and the back door of the second floor is also ground level. I chose to place the detectors in the guest room, which is on the first floor and in the back exterior corner of the house. The back wall and 3/4 of the side wall of the guest room are underground exterior walls, and thus this room would be one of the most susceptible to radon infiltration from the ground. The room that serves as my office and workout room is next to the guest in the front exterior corner of the house. Two of its walls are also exterior, but only about 1/3 of its side wall is actually underground. However, there is a crack in the slab about two feet long in the office, so I considered whether the test kits should be placed in this room. [Due to the extensive renovation I’ve been doing on this house, I know where all the cracks and openings are.] That crack could serve as a major route for radon to enter the house. However, I ultimately decided that the guest room would be more susceptible to radon infiltration because of the amount it is underground.

After choosing in which room to place the detectors, I then found a good location that was far enough away from an exterior wall and above the floor. I then proceeded with the testing protocol. I unscrewed the containers and let them sit for four days. Whew, that was exhausting. I deserved a drink after initiating that test. Here is one of the detectors unscrewed. It’s quite simple looking.

Radon detector open to run test

After I let them sit for four days, I screwed the caps back on, filled out the form that came with them, and mailed them into the lab. It cost $30 to have them tested, so with the cost of the kit, the entire thing cost me $50. I consider $50 a small price to pay to make sure I am not unknowingly breathing in a carcinogen everyday. I’m currently waiting for the results from the lab, and I will update my blog when I get the results.

One final note, I said at the beginning of this post that winter is the best time to test for radon. The reason for this is winter tends to be the time that the radon concentrations in a house would be at the highest. When the weather is nice, people tend to open windows for ventilation instead of using the AC or heater, and people just tend to open doors more often to go outside for whatever reason. Thus in the winter, the house is more closed off, and radon concentrations can build up due to less exchange of the indoor air with the outdoor air. Where I used to live in south-eastern part of US, I probably had windows open more often in winter, as I constantly used the AC in the summer, so this might not hold true. That and the fact that indoor air concentrations can vary day to day, is why experts recommend that if you get high levels detected with a short term test, you consider doing a longer term test such as over several months, to determine what the longer term average is. The test kits do have false positives, especially at lower concentrations, so if you test your house, and it comes back high, once again, don’t panic. Test your house again, this time with a longer term test, and see what the longer term concentration is, and then determine if you need to take action. However, don’t remain ignorant about the risks. Test your house; it’s important and could save your life.

For more information:

Ai Weiwei: According To What?

Posted on February 6, 2013 by geek

This weekend I went to see the exhibit of Ai Weiwei’s work called “According to What?” that is currently at the Hirshhorn, part of the Smithsonian. Like I would imagine many people, I was somewhat familiar with him as a Chinese activist, but I had never actually seen any of his work. The exhibit features sculptures and photographs, but I found the sculptures to be the most interesting. I don’t presume to know almost anything about art, especially modern art. I like some things. I don’t like other things. I simply don’t get or understand many things. I am not sure I understand much of Ai Weiwei’s work, but much of it did make me think, which I think is part of what he wants.

Ai Weiwei’s Light Cube

Possibly the biggest sculpture at the exhibit is Light Cube. It is this huge cube with amber colored beads or crystals on the outside and lights inside. I really don’t know what it is supposed to represent, but it is really cool to look at.

Ai Weiwei’s Straight

Another large sculpture is Straight. It is made of 38 tons of rebar recovered from collapsed schools in Sichuan, China after the 2008 earthquake. The rebar was evidently carefully straightened after it was recovered. Straightening rebar is no easy feat. Photographs of the devastation are on a nearby wall. The sculpture certainly makes you think about the devastation of the earthquake. The way the rebar is placed makes me think of a fault line and topography, but I have no idea if, assuming that is what it is supposed to represent, it is an accurate representation of the Sichuan area. As an engineer, I love the use of rebar for art.

Ai Weiwei’s Bowl of Pearls

Bowl of Pearls is honestly one of the prettiest things I have ever seen. It is two huge bowls (as in about 3 feet in diameter) filled with freshwater pearls. It is absolutely gorgeous, and I have no idea what it means.

Ai Weiwei’s Bowl of Pearls, unclose view of pears.

The pearls are different shades and so pretty and luminous. Yes, I like pearls and shiny things. All I wanted to do was put my hands in there and run them through the pearls. It is like a giant zen sculpture or something.

Ai Weiwei’s Colored Vases

Colored Vases causes me torn emotions. I love the colors, and the vases are a lovely shape. I think the way the paint applied and allowed to run down causes a really nice effect. However, the vases are really old, from the Han Dynasty. Dipping these ancient vases in industrial paint strikes me as defacement. Evidently that is what he is trying to do. These are supposed to be a statement about the Chinese state. The vases are innocent victims in his political statement. I am very curious just how many Han Dynasty urns there are lying around that people can buy or just find. Can you just go buy one? How did he get a hold of so many of them?

Ai Weiwei’s Moon Chest

Moon Chest consists of several hollow wooden boxes lined up on a curve. Each box has four circular openings that are precisely cut so that they mimic the stages of a lunar eclipse.

Ai Weiwei’s Moon Chest, view of the aperture

The fun thing about this sculpture is that it turns almost everyone into a child. Almost everyone who walked by it and between the different boxes got up close and looked through the apertures and moved around to see how the view changes.

Ai Weiwei’s Divina Proportione and F Size

Divina Proportione and F Size are two giant, wooden buckyballs. I immediately thought of Buckminsterfullerene, but then again, I am a geeky engineer. I suppose the less geeky inclined might see soccer balls or geodesic domes. I have no idea how well they would roll, but yes, I would like to see them roll.

Ai Weiwei’s Forever

This is why China is having such horrible air pollution. People are having to take cars because Ai Weiwei has taken all the nice bicycles and used them for art. I was thoroughly impressed with how well he fit them together. Parts of the bicycles were cut off, and then they could be joined with bolts and nuts. The joints are really well done. Yes, clearly I am engineer as I was analyzing the construction method of this sculpture not what it means.

All of the above photos were taken by me. The Hirshhorn allowed non-flash photography for personal purposes. A few of my photos are slightly fuzzy because they were taken in low light without a flash and thus needed a longer shutter speed. I make no money off this blog, thus my understanding is this falls under personal use.