I will offer a less then one year renewal if  they ask and  it works for everyone. 

Explain to them that it your legal right to end their lease (or rental agreement) within the bounds of what is laid out in it  (notice of X days, non-renewal, etc.) but you want to talk to them so you can reach an agreement.If they really really really want to stay, maybe they'll move into the other side once you've renovated it?  

Yeah, ours just renewed and they added an extra charge since it wasn't our primary residence.  :( 

Per their website http://www.dllr.state.md.us/license/mhic/ "The Commission has a Guaranty Fund (The Fund) supported by licensed contractors, who pay a Guaranty Fund assessment when they obtain their Home Improvement license and each time they renew their license.

I will renew the lease on those properties with the LLC as the landlord.  

@Michael Rigoni, I agree this is a delicate situation, but the compassionate thing to do would be to let the tenant know you do not intend to renew his lease because you want to make necessary repairs and improvements.

I can't seem to find a letter online that states that I won't renew his lease and he needs to vacate the property when the lease expires.

he renewed his lease. 

My question is, when do I tell the tenants I won't be renewing their lease and will be selling the property?

Many restrictions require that you go through the restriction process every time the lease expires/renews (so that others on the waiting list haev an opportunity to rent their unit).