My Credit Union has what they call a Near Mortgage rate of 4.95%.
Looks like you can borrow up to €100,000. On their calculator anyway, the max term is only 5 years, a very short term for a big loan, I wonder is there any flexibility there.
Some Credit Unions can do a secured loan as second charge on property, that would be best rate from them if you can get it but term probably limited to 10/15yrs
As far as I'm aware it's actually an unsecured loan. Or at least in the cases I'm aware of.
Considering a lot of credit unions charge 5%+ on loans 100% secured by shares, I can't imagine them having much discount for a 2nd charge which is effectively worthless until the property is sold/ transferred.
High spec shed essentially. They, and other similar structures can be a great option for extra ancillary space. You are allowed up to a maximum of 25sqm total area of all shed like structures on your property without the need to apply for planning providing you will have at least another 25sqm of garden space remaining. They can not be attached to the house or used as habitable space unless specified to be fully compliant with all building regs.