Sunday, June 06, 2010

Spatial Distortions

So far with this project I’ve been having a hard time estimating time and materials. I think this is happening for two reasons. First, both the foyer and stair hall are larger than they seem. Second, the wall for the front door is the only wall I’m completely doing from scratch, and most of that wall is door and transom. Everything else is 3-feet here, 5-feet here, a little spot there. Taken individually, they don’t seem like very big spaces, but collectively it’s a lot of wall.

I was able to get the scratch coat on about 75% of the walls by mid-week. I finished that up on Saturday and then started in on the brown coat. For me, the brown coat is where I really earn my money. If I was getting paid, that is. I mixed and moved a lot of plaster this weekend. The brown coat is when I bring it out to level with the remaining walls. This is the last step before the skim coat, so I want it to be level and smooth. The skim coat is pretty much as it sounds. It is not going to hide many imperfections in the previous coats.

The scratch and brown coats are on the stair hall, front door, and old phone wall.

What remains is the parlor and dining room walls. I could have gotten more done today, but I ran out of plaster.

The plan is to buy another 2 bags of plaster on Monday or Tuesday and see if I can finish up the brown coat mid-week. Then next weekend I will do some clean up and build the scaffolding in the stair hall. Although I’ve gotten very good and getting plaster from hawk to trowel to wall without slopping it on the floor, the key to the whole process is the consistency of the plaster. It is a bit of a balancing act. You want the plaster to be thin enough that it affords you a long enough working time, but not so thin that it is hard to work with.

With the brown coat I am making larger batches of plaster than for the scratch coat. If I make it too stiff then it becomes harder to work with as I empty the pail. The trick is to get it thin, but not too thin. I had a bitch of a time getting it to be the right consistency today. We’ve been having some unseasonably rainy weather, so maybe that played a part. I’m not really sure.

What this means is that I made more of a mess today than I have on previous days. Hence the clean-up day next weekend. When plastering in a the corner I find that I must stand like dancer all spread eagle with arms and legs stretched out. The corners can be a bitch and you need your legs stretched out to get the leverage and your arms must be stretched out to the get hawk out of the way.

So what happened a few times today is that I’m plastering in a corner with the hawk full of plaster in my left hand stretched out behind me to get it out of the way. While I’m concentrating on getting the plaster smooshed in to the corner nice and tight I suddenly hear a ka-flump! as the thinly mixed blob of plaster slides off the hawk and on to the floor. In fact, this only happened twice today, but I inevitably stepped in the cow patty sized blob of plaster and tracked it around.

The floor is well covered, but after the grinding of the grooves and now the plaster mess, I just need to clean it up and start over. So if I can get the room cleaned up and the scaffolding built next weekend I should be able to skim coat the weekend after that. With that, the plaster will be done and it will be on to woodwork.


Al said...

It's so nice to have you back on a regular basis!

Greg said...

It feels good to be working on a project again, but oh, the mess...

Holyoke Home said...

At the risk of sounding like a TOTAL novice:

What is the difference between the brown coat and scratch coat, and why two coats?

Greg said...

Since I now have 5 rooms under my belt I'm feeling like a journeyman plasterer, but in reality I'm still a novice myself, so take this explanation with a grain of salt.

The scratch coat is the first coat that goes on. For me it is 100% Structo-lite. It is rough and it forms the keys that holds the plaster to the wall. I once saw a guy actually scratch the dried stucco scratch coat with his trowel before applying the brown coat. The expanded perlite in the Structo-lite makes it hard for me to get an absolutely smooth finish.

The brown coat can be the last coat in some cases. In my house, for instance, there was no finish-coat applied. For me, I use a 50:50 mix of Structo-lite and Diamond Finish plaster. The benefit to this mix for me is 2 fold. The Structo=lite has a longer working time and it is also less expensive than the Diamond Finish plaster. I get this as smooth as I can but not as smooth as the finish coat will be.

For the finish coat I use 100% Diamond Finish Plaster. The finish plaster is mostly lime and has no perlite in it, like the Structo-lite. The wet mix is buttery smooth and cures fast. This coat is no more than a 1/6th of and inch thick.

I suppose you could but on both the scratch and brown coats at the same time, but that would be a lot of plaster to put on the wall at one time. For my house the finished thickness is 3/8ths of an inch off the wall. With the keys though, it is 3/4 of an inch thick.