Any lease of worthiness will have a clause prohibiting the property being used as a business which would include using the address for business purposes.
IMHO, any person wanting to use his "home" address as a business address would want to be sure that he was going to be living there for the foreseeable future. No point in setting up a serious business then a year later having to change address - but that's just my opinion.
Furthermore, the Residential Tenancies Act also states that one of the types of dwellings excluded from the Act include:
(a) a dwelling that is used wholly or partly for the purpose of
carrying on a business, such that the occupier could, after
the tenancy has lasted 5 years, make an application under
section 13(1)(a) of the Landlord and Tenant
(Amendment) Act 1980 in respect of it,
Again under tenant obligations, we find:
(m) not use the dwelling or cause it to be used for any purpose
other than as a dwelling without the written consent of
the landlord (which consent the landlord may, in his or
her discretion, withhold),
Not sure am I explaining myself enough here, but hopefully someone can help.
Thanks
M
From your explaining, I get the impression that you want to be a non-tax/legally compliant landlord.
If you do not seek written permission from your mortgage company to rent out the property, any lease you have (whether verbal or written) may be invalid, as most mortgages have a clause prohibiting such action.
Finally, as an aside, the easiest way to turn friends into enemies is to work for them or rent to them. Friendship tends to take advantage of friendship with detrimental results.