Sealant for redwood and concrete

Thompson’s Water Seal, IMHO.

-- Dave; Lansing, Kansas

Real Tung Oil diluted about 50/50 with mineral spirits will seal the stone and add some protection to the redwood.
Additionally, you might want to consider a Spar Varnish for the redwood.

-- 温故知新

PLEASE look into a product by Sikkens paint called Cetol SRD.
We have used it on both pine and redwood. It will last outside, without need of touch up, for several years.
When protected, indefinitely.
We did all our deck boards before we installed them. Several drips on to the concrete under the saw horses. An 1800 psi power washer after paint thinner followed by TSP will NOT remove it!

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

Thanks for the replies so far. My wife read some suggestions for Tung oil elsewhere, which won’t be cheap, but sounds workable.

Gene, I looked at the Sikkens product, and went to their MSDS page. The warnings on that page read like the warning for a toxic waste dump! This is for the inside of a greenhouse. Imagine rubbing your broccoli against this stuff before eating it. (assuming you like broccoli) It’s not that we will be spraying this stuff while there is stuff actively growing in the greenhouse, but I don’t want my to grow stuff in an enclosed space with that many bad chemicals.

I didn’t check out the MSDS on Thompson’s, but I suspect it has a similar list of things I don’t want on veggies.