Friday, April 25, 2008
Lime Rendering
Apart from a couple of small bits of in-fill around the dormer windows all the plasterboarding upstairs is now finished. I didn't have any scrap pieces large enough and I didn't want to use up a whole board just for a small bit. Once I start plasterboarding downstairs I can use any larger off-cuts to finish upstairs.
The last couple of days have been spent lime rendering an internal cob and stone wall. I could have just stuck plasterboard over it but I thought it would look a little more authentic and rustic with a traditional lime render.
The lime render is made up of just lime (Chaux blanche hydraulique naturelle), sand and water. The instructions on the bag said one sack of lime (35kg), 11 buckets of sand (10L buckets) and two buckets of water. However after chucking the water, lime and half the sand in the mixer we realised the mixer was too small and had to spend along time juggling the contents of the mixer and two wheelbarrows taking half out, adding sand, removing some, adding back etc. etc. Not a good start.
Never having plastered before it was a real steep learning curve and through trial and error we finally got all the render on the wall. At first it was a real problem getting it to stick. I had brushed all the loose dust off, but just pushing it on with the float didn't really work very well. The mix was quite creamy, but gritty with the sand. Wetting the wall with a water spray helped alot but the technique that really worked was to throw the render onto the wall, flicking it quite hard, then spread it out with a float.
The hardest part was keeping a wet edge as you worked. If the edge dried out at all it was really tough to blend in the adjacent new render without leaving a line or bump.
With hindsight, I think we should had wetted the wall much more, and thrown the lime render much harder at the wall. As it dried out it did crack in quite a few places and a couple of spots sounded a little hollow where it had not stuck quite right. It certainly looks rustic tho'
Overall we covered about 30 square meters of wall in a day and a half and used around 6 bags of lime. Really hard work and not something I want to do again in a hurry.
| 11:32:59 AM
Lime Rendering
