I have powderpost beetles in a newly installed ash wood stairs. The installer has agreed to strip the wood so it can be treated but my exterminator does not guaranty treatment because only the top can be treated and he doesn't beleive that the chemicals would penetrate more than a 1/4 " of the one inch thick wood. The installer has offered to also drill holes every 6 inch to help the chemical penetration. I contacted another exterminator and the suggested heat treatment which is guaranteed for one year.
I have read your articles and find them very helpful and value and appreciate your opinion on best solution.
Thanks.

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