Lime Washing the Barn

How to lime wash a barnI’m not sure what got the idea of lime washing or white washing the barn in my head exactly.  I think I was looking up information on goat kids when I brought home Nelly and Alfie and came across the mention of white washing on the Fias Co Farm webpage.  I’ve had issues with lice and mites on Molly (my full size elderly Oberhasli) and the barn does always seem a bit dark, especially the fully enclosed tack room, so it seemed like an inexpensive option to lighten and brighten it up and hopefully make it less hospitable to the pests.  One of the sad things is that lime/white washing is a lost skill.  It used to be extremely common but almost no one does it anymore.  I just love learning and perpetuating lost arts so I’m sure that contributed to my interest.

The first challenge was actually finding hydrated lime.  I looked up all the variations so I could make sure I found the right stuff since there’s several types of “lime”.  Hydrated lime is also known as:

  • Calcium Hydroxide
  • Builders Lime
  • Masons Lime
  • Slake Lime
  • Pickling Lime

Hydrated lime is truly lime and shouldn’t be confused with “ag lime” (garden lime, agricultural limestone) which is pulverized limestone and primarily calcium carbonate.  It also shouldn’t be confused with dolomitic lime which contains calcium carbonate and magnesium.  Both are used primarily as soil amendments.  Hydrated lime also shouldn’t be confused with “quicklime” which is calcium oxide and is used to create hydrated lime.  There’s a lot of confusion around lime names though AND add to it that hydrated lime can also be used as a soil amendment (with proper considerations).

I was pretty sure I knew what I was looking for at this point, but I ended up going to three hardware stores before finally finding the right stuff.  That was of course after every one of them tried at least once to insist that ag lime or dolomitic lime was what I really wanted.  Typically hydrated lime will be with the masonry products (grout and cement), but ultimately I found it in the garden section.  The kind folks that helped me find it said the primary customers for it are the local golf courses who use it to help green up the grass.  I picked up a 35lb bag for around $13.

There are some things to consider before lime washing.  First, the surface needs to be porous.  I did slop it over some metal hinges and plates andHow to lime wash a barn - in progress it seems to stick, but I understand it won’t cover concrete well, if at all.  I was lime washing unfinished wood, mostly plywood and pressure treated posts.  Secondly, it’s water based so a basic lime wash will come off with moisture.  It’s best used in areas that aren’t exposed to the elements.  From my research there are things you can add (glue) that will help it stay longer and/or be water resistant but my application was interior  so I wasn’t concerned.

Hydrated lime is alkaline so it wicks up moisture.  If you regularly expose bare skin to it you will severely dry it out to the point of damage.  I wore a pair of rubber gloves to protect my hands, but if you do get some of it on you it’s not a big deal. I sure got splatters of it everywhere.  It’s consistent, regular exposure that’s the problem.  At the end of a painting session I just wiped the splatters off my skin using lemon slighting more acidic and I didn’t feel like smelling like a pickle.

There are a variety of recipes out there and folks go for varying consistencies.  I decided to go with an actual wash which is more liquidy than paint.  A lime wash is supposed to adhere better because it can get in the cracks and crevices and the surface can soak it up.  Thicker consistencies may be more paint like but can flake and crack when dry.  The consistency folks seem to aim for is “milk like” but mine ended up more like skim milk than the good raw whole milk I get from the local dairy.  I used the following recipe:

  • 8 pints hydrated lime
  • 2 pints table salt
  • 8 quarts water

I’m using pints and quarts because I always have mason jars around and it was an easy measuring system.  I mixed 1/3 of the lime and salt in a 5 gallon bucket and then added 1/2 the water.  I mixed it with a paint mixer on my electric drill to make it easy.  Then I added the next 1/3 of the lime/salt, then the remaining water, and mixed.  Lastly I added the remaining 1/3 of the lime/salt and mixed.  Some instructions say to let the mixture sit overnight, but I didn’t for my test patch.  It did sit overnight before I did my first painting session.  I didn’t notice any difference between the applications so I don’t know that letting it sit is necessary.  The lime will settle in the mixture, it doesn’t fully dissolve, so you will need to mix it from time to time to keep it distributed.

To prepare the barn I grabbed the broom and swept the walls of dust, dirt, and spiderwebs as best I could.  I used a cheap paint brush and started sloping the stuff on.  I did have to kind of work it in to the wood grain a little bit to get even coverage.  It seemed to want to bead a little on some spots but I got a little forceful and eventually it would stick.  It definitely goes on very thin looking.  I stopped after a small patch because I thought for sure my recipe was off and it wasn’t going to do what I expected.  I left it to dry overnight and when I went back down the next day I was shocked at how opaque it had become.  Then I started working on the walls during the heat of the day and I could see it drying in about 15 minutes and going from quite transparent to fully opaque.

How to lime wash a barn - dryingSo far I don’t have any issues with the lime washing and it did what I was expecting.  I did catch little Nelly licking the (dry) lime washed door, but it didn’t seem to be an issue and she lost interest pretty quickly.  The wash is wearing away where the little goats try to climb the wall to get to Molly’s feed dish and behind the manger where I drop flakes of alfalfa down from the loft, but I kind of expected that.  I still need to do the interior tack room, but that will require a lot of moving items so I’ve been putting it off.

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