Go to www.woodspecialist.com for information on log home restoration on the west coast.
I prefer to sand entire house over cob blast. It makes for a better prepped surface and the final product looks better. Cob blasters are good for hard to reach areas like corners. I would rather use glass media than cob.
You could also use Osborne Buffing Brushes that are used with a right angle grinder.
Osborn Brushes are great for after blasting buffing. It would be very labor intense and expensive to do the finish removal, as these brushes are $75 a brush, and one brush won't go very far when you are using them for finish removal. They are simply just an expensive buffer. They are the best product we have found for buffing logs.
Bill, rotting organic material? Is that what mulch is made of? We are talking a trace, or a dusting of organic dust left on your lawn or landscape, after clean-up. What rodents are we attracting? If you are talking carpenter ants and borates, any reputable restoration company will do a borate treatment after finish removal.
If the concern is rodents, crushed recycled glass could be used instead for media blasting. Just as big of a concern with raised grain from blasting is compressed grain from sanding to remove a finish.
I'm currently taking estimates from local restoration contractors and am seeing labor (not including anything else but labor) estimates in the range of $1.60 to $2.00 per sq ft for blasting, $2.50 to $3.00 on log end grinding and around $1.00 on osbourne brushing after the blast. Our estimates sq ft of exterior log to be refinished is in the neighborhood of 8,300 sq ft, not sure in size of job has any effect on labor cost.
The cost of restoring a log home rarely has anything to do with square footage, our company estimates the cost of log home restoration by how many days it will take our 4 man crews to complete a project. After almost 20 years of year round log home restoration work on the west coast, we know exactly how much materials and labor goes into each project. Things like height, type of existing finish to be removed, access by ladders or lift, roof type, landscaping, and location all are factors that are considered when taking on a restoration project. So trying to figure out a square foot price is difficult to compare log home to log home, in fact, if any contractor does quote you these prices over the phone, ect. I would be willing to bet that they would change their pricing once they show up at your log home and discover you have an elaborate japanese garden with ponds and a pool in the backyard, are 2+ stories on a hillside or sidehill, have a steep pitch metal roof w dormers, or other unseen obstacles or difficulty. it would be not the same price as a rambler log home in a meadow with no landscaping. Just saying, make sure your contractor has a clear understanding of the project or extra charges will come your way-use a professional company with hundreds of references and call them to find out what your experience may be. It is always best to get a solid estimate price, as labor on log homes has a way of always being more than you originally thought at the beginning of a project, especially if you have little or no experience with log home restoration.
On a side note, contractors who sand off old finishes crush and seal the grain, sand unevenly, leave grinder marks in the corners and on adjacent logs, the logs surface never look uniform, it's almost impossible to get all the failed old finish from joints, cracks, fissures, and knots, and the finish applied never lasts long due to the mill glazing during the heavy grinding/sanding process. We know this as fact, as we have done sanding in the past for customers' who are adamant about that type of procedure (they must have read it on the internet), but we have seen the results compared to our other methods and it just does not compare in quality, is more labor intense (more cost), is not effective with certain types of finishes (muck up sand discs) and is, in our opinion, not a preferred method. That being said, I know a lot of guys are doing that, please don't respond to my opinion, as it is only an opinion based on our experiences. Have a great day everyone and I hope this helps someone who is debating which way to go.....
Also with square foot pricing, I have never seen someone measuring actually take the roundness of the log into account. A 20 foot long x 20 foot high log wall is not equal to a 20 X 20 flat wall. The 20 x 20 log wall is not 400 sq ft, you actually have to multiply by 1.6 if the logs are for example 12" round logs. So your 400 sq foot measurement is actually 400 x 1.6 = 640 sq ft. The margin of error with this mistake is 60%. Most often the person doing the calculation didn't take the time to go back to geometry class in most cases and figured that 3rd grad multiplication was all that was necessary.
If there are any math majors here, please start a discussion on how to measure a log wall as I think I have just scratched the surface on this topic.