By the early 1990s, Rwanda, a small country with an overwhelmingly agricultural economy, had one of the highest population densities in Africa. About 85 percent of its population is Hutu; the rest is Tutsi, along with a small number of Twa, a Pygmy group who were the original inhabitants of Rwanda.
1 Power sanding, stain and seal â This is a very aggressive procedure normally used on decks that have not been well kept or are changing color. The average cost is $2 to $4 per square foot.  Light sanding, stain and seal â This is a general annual treatment for a deck.
1 Depending on the size and layout of your deck, actual costs could be less than $500 or $1,500 and up. 2  For sealing alone on a 250 square foot deck, expect to pay $300 to $400. 3  Staining a deck of the same size might cost $400 to $600. 4  Again, expect costs to rise for larger decks. Again, expect costs to rise for larger decks. 2  A gallon of deck stain or sealant costs $25 to $40. 3  To seal a 250 square foot deck, plan on using two gallons ($50 to $80) , plus assorted brushes, buckets, and rollers ($20 to $40) for a total materials cost of roughly $75 to $150.