Do Log Cabins Have Insulation?


Insulation in a log cabin is a must for the cold days spent in a cabin. I did some research and it has proven to be quite a topic.

Do log cabins have insulation? The short answer is no, there is no added insulation inside logs. However, the logs actually ARE not only decent insulators, but they also act as “thermal batteries.” The only problem is that wood expands and contracts over time which creates air gaps where heat or cooling can escape.

Now I do not have to tell you how bad it would be to be losing heat in the winter. I am going to tell you some thoughts I would like to share that I have learned about how to combat the problems that come with log cabins so you can more fully enjoy what you have.

Putting the Damper on Air Leakage

Like I mentioned before, wood expands and contracts depending on the temperature or the moisture in the air. It is very temperamental. Because of this, over time log walls for a log cabin will start to have air gaps/leaks that will really send your heating or cooling bill through the roof!

Let me teach you a bit about wood.

Air-dried Logs

Okay, so most houses are made with air-dried logs. That means they let them dry as a normal process and then use them. The problem is that these logs are still about 15%-20% water when put on the house and assembled. Because of this, as the wood dries over the next few years the wood will shrink and create the air leaks.

Fortunately, with houses, you don’t have to worry about that because there is drywall and then the outer layer of the house. This won’t be a problem with the average house but with a log cabin? Yeah, it won’t work because all you have is the wood.

Let me explain how to fix this problem.

Seasoned Wood

Okay so this is not about spices like my younger self would have thought. Seasoned wood is wood that has been dried for a long period of time in a protected area. Some wood can even be dried in a kiln and that’s called kiln-dried, unsurprisingly.

Generally the wood is dried for a minimum of 6 months before they are used for any construction. This is probably one of the best ways to accomplish your goal of getting rid of air leaks.

Here is the most effective seasoned wood to use for your log cabin:

  • Cedar
  • Spruce
  • Pine
  • Fir
  • Larch

Basically any tree you find on the west coast will work. Okay but jokes aside, these are what you want to look for.

Fortunately, most of the people you would buy them from have knowledge of these potential problems and they will kiln dry them before selling and installation.

Caulking and Sealing

Ask the people you buy from questions that you may have. Some suggest using caulking or some plastic sealant to seal the gaps. Caulking will take some inspection on a frequent basis because over time you will be to reseal. I would use clear caulk because it blends in.

Since caulking is more elastic than chinking materials, it is much better for touching up an area. It’s kind of the little guy that holds everything else together.

When caulking a crack or space that is deeper than 1/2″ then you should invest in some backer rod. Here is a great product. You can find many sizes but I just included this one because it will work with the 1/2″ inch deep fictional gaps I am talking about.

Backer rod is for filling gaps that are large because caulk in the can never lasts as long as you think it is going to. You may not think 1/2″ is big but when your wall is 20′ wide that’s somewhere around 120 inches of caulk. I hope that explains why you need some backer rod.

After you insert the filler rope then just caulk it up! This rope stuff is water proof and it seals really well. You can’t go wrong with it.

Chinking

Chinking is not only a funny word but also a good, elastic, stylish way of sealing a log cabin. It looks like the old-fashioned Portland cement-based mortar and it is used to seal the joints between logs. This stuff is most effective for sealing long (like really long) strips of gaps between logs. It looks like what they used to do years ago.

I would recommend this over caulking for the big joints between logs and if you want your cabin to look old-fashioned. Caulking works better for short touch-ups.

Chinking is to logs as mortar is to bricks.

Log Cabin Hub

Logs are susceptible to moisture. Logs can bow, kink, crack, etc. The environment will change which will make the logs expand and contract. Chinking will seal the logs from outside elements like the rain or snow. This stuff also protects the logs from standing water that could eventually rot the wood.

Logs aren’t perfect and they aren’t going to meet exactly. This is why chinking is important. It creates a nice seal to cover up what the logs are missing. This is the ultimate way to have a good seal and no maintenance. The last thing you want to be baby your cabin while enjoying it.

When you start chinking, you’re going to want some backer rod again for this. For the same exact reason. This will allow for better adhesion and allow the chinking to settle in for the most sealing potential it can have.

There are two kinds of chinking: Synthetic and Mortar. Here is some more information regarding chinking and what either of these types do. This page also has content.

Controlling the Moisture

It’s no secret that trees are meant to hold water. It’s one of the ways they grow. Even after a tree has been cut down and made into wood for various purposes, it still retains the tree cells that absorb water. Because of this, log cabins are something we call “hydroscopic.” That means they absorb water rapidly.

To combat this, you are going to want to have wood that is seasoned and treated. You will want it waterproofed and insecticide-treated. Every few years you will need to reapply these same exact treatments to obtain maximum control of the moisture in the wood for your cabin.

Is Treated Wood Safe?

Some of you you may not care for this at all and go about your daily lives, but for those of you who do care, here is what I found.

A lot of pesticide on wood is Chromated Copper Arsenate (CAA). CAA contains something called arsenic, which is rat poison. Some people have said that the insecticide can seep out of the wood. I can see that but I don’t know for sure. I have not researched that, but here is some information you might want.

The U.S. Forestry Service and U.S. Environmental Protection Agency both say that that CAA is safe if used appropriately. The EPA says the health risk is low to moderate.

Roof Insulation

To assume that your cabin will insulate itself because of the thick wood would be completely wrong and ignorant. Most of the loss of heat will happen through the roof and the floor (I’ll get into this one in a bit).

Since this is a problem, we really need to cover how to insulate your roof. This part is a little bit tricky but it can be done. No problem.

When roofing, before putting the shingles on the roof, You want to start with moisture in mind. You’re going to want to cover the wood underneath with Tyvek, Kingspan or any other moisture resistance membrane. This will do the job to keep out moisture if any creeps in underneath everything.

You will want to staple down all of this so it lays flat and smooth. It creates a nice temporary roof. Along with that, it keeps the warm moisture from inside the house getting into the insulation in the roof as well as keeping moisture outside from getting in. It is fantastic.

Make sure that you measure how much you need before you buy because you don’t want to have a ton of excess. If your cabin is simple and just has a single roof, measure one side of the roof and then times it by two. 

There are many things you can use for insulation. You can use manmade products which are effective like Kingspan and Celotex. If you’re more on the natural side of life, you can use things like wood fibre or sheep’s wool. The natural stuff will probably be more expensive.

Some of the best insulation out there is barricade wall panel. It is lightweight and structurally sound. They use this stuff for insulating basement walls but it will work just fine with your roof, trust me. Look to this video for more information.

Barricade wall panel also works perfectly with putting shingles on afterwards. It’s user-friendly and not very expensive.

When you lay down insulation board, you’re going to want to make sure that the boards are flush with the edge. You don’t want to leave room for moisture or leaks at all. This is crucial. Make sure the trim is also cut well.

Do everything in an orderly fashion. After you get the insulation on there, cover it up with shingles. Start from the bottom and then work your way up while overlapping just a little so that when the rain and snow comes, the water rolls down and off the building instead of into your insulation.

After doing all of this, your roof will be insulated well and can keep the warm moisture in the building and the outside moisture out. Now let’s talk about the other half: the floor.

Floor Insulation

Floor insulation is so important. It will save you tons of money in heating for your own log cabin. Insulating your log cabin floor will save you up to 20% of your yearly heating costs in the building.

Insulating your log cabin floor will save you up to 20% of your yearly heating costs in the building.

Once again you want to install a moisture resistant membrane. Use the same stuff. The Tyvek or the Kingspan. It will be underneath the cabin on the ground instead though. This acts as a barrier from the water coming in. This will keep your floor from being damp and the underneath of the cabin will be dry.

After that, you’re going to want to put some pieces of wood directly on the membrane to give your cabin stilts if it doesn’t already have some wood to raise it up just a bit. You want about a 50mm gap between the cabin floor and the membrane. There is a picture on this website that will show visually what I am talking about.

After this, you will lay your insulation in whatever way it needs to be. Fill the holes and cracks between the joists. Joists are the wood that comes up to support the flooring. Make sure you cover any gaps to help keep the heat in and your heating bill way down. Check for cold spots and see what you can do to fix them.

The insulation should come up flush against the joists and then check that the floor will lay flat on top of that. Then lay down your entire floor and your bottom portion of your house is done!

Window Insulating

Choosing windows is not only important for look and style but also for keeping the heat in. You want something stylish and beautiful but also something that is energy efficient. 

Window Glazing

When I think of the word “glaze,” I don’t think of windows. I think of donuts. This is a new concept to me so I will try to explain it.

There is this putty that is a glazing compound which holds the glass in place so it doesn’t move around or break. It also keeps the weather out. This stuff can last for decades so it won’t need to be changed much.

Now, there are different levels of window glaze. They are pretty simple: single glaze, double glaze, and triple glaze. It will cost more with each glaze so figure out what works best for you. Single glaze being a mild climate and triple glaze being harsh climate.

If you’re into style and you want to have a little bit of extra tint to your windows there are bronze or gray tints available. If you do that, it will create a darker room, so keep that in mind.

Window Framing

Frames help the window’s look and create a sturdy holding for the window.

Aluminum windows are light but strong frames. These work best for custom window designs for the artsy cabin maker.

The wood framing is for the traditionalists out there. It is also good for custom design. The only problem is can create heat loss.

Vinyl is versatile and has great insulation. You can get many style, shapes, and sizes. They have great moisture resistance if that is a problem for you.

Fiberglass frames are the beset choice you can make in energy efficiency. It’s a strong and durable material. They require little maintenance.

Window Styles

You may think that window style is all cosmetics but it is not. Here are some thoughts I have.

Awning windows pivot at the top and opens from the bottom outward. This keeps moisture out.

Transom windows are rectangular windows that go above another window or door hinge. It’s the tiny window above the others.

Casement windows are hinged to a side jamb. They usually open with a crank or slider bar. There are great for ventilation. They are known for their weather-tight stability.

Bay Windows are three windows in one, basically. The middle one is fixed and will not move. The two on the sides flank the middle angling the wall. These provide a great view of the area from different angles.

There are other kinds of windows out there that you could find and I will leave that up to you.

Good luck with insulating your log cabin!

Related Questions

Are log cabins energy efficient? The log cabin energy efficiency is all in the wood’s insulation and thermal mass. These homes are great and are extremely efficient.

How much do log homes cost? Now this question is very objective. It really depends on how big you want it to be. It is possible to build one on a budget. Some cost $20,000. It will really depend on what you are looking for. It is an investment but a great thing to have if you have the money.

Are log homes more expensive than traditional homes? Actually, log homes are less expensive than timber frame homes. If you hand craft the log cabin, it can cost nearly as much as timber frame homes. It really depends on what you are making and the size of the structure.

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