AIBU to say no to my son and partner moving in?

Does your garage have kitchen and bathroom facilities?
If not, what's their thinking around that?
Is there room for them and their visitors to sit in there in relative comfort?
Realistically this won't work, they seem to be doing a lot of blue sky thinking, time for a reality check.
Unless they are planning to be mortgage free won't they need evidence of steady jobs and good salaries to get a mortgage? So both leaving their jobs may not be the best idea. Some economies and maybe taking an extra part-time job each to save a deposit may be more sensible.
The only way we could scrape together a house deposit was to both work Mon-Fri full-time then both worked in a pub evenings and two shifts Sat and Sun. Totally knackering but no pain no gain. Maybe they might consider doing similar if you make it clear that running home to mummy is not an option.

Conversation goes something like this.

I sympathise with your situation, however your proposal to live here does not work for us. We do not have the space and do not want extra pets. Your £50 a week would not cover the extra expenses of you living here and we cannot bank roll you.
However, maybe look at selling your extra furniture and moving to a 3 or 4 bed shared tenancy house. That way you can stay in your jobs and save money. Maybe set out a financial plan where you can both save around 30-50% of your wages each month. You will need to be extra frugal and go with for the year but it will get you where you want to be.
I wish you all the luck and will support you by giving advice where needed.
*Or offer to store their furniture in garage while they do shared tenancy, to show your 'support'

They're going to save for a house by giving up their jobs. What a pair of geniuses. As we used to say in the 80s OP, "just say no".

That’s a NO from me
Followed By a future NO to looking after their pets while they travel

And why the hell should she do that?!

OP…couldn’t you sleep on sofa downstairs and give them your bedroom?

I think this is meant to be a joke, isn’t it?

If not, why on earth are women always being asked to give up, sacrifice, make do, make room? Especially women who are either single or have the temerity to want to sleep alone in their own space.

Funny someone mentioned step parents as no one is asking it of the step dad!

i dont think you are being unreasonable to feel you don't have room for your adult son ,his partner and pets or that you dont want the disruption of your DS visiting family.. From what you have said you don't have room.That said ,in the current climate leaving good jobs without having found another job is not wise and storage cost are expensive. They need to find another way to save for a deposit. Could they economise, move to a cheaper area ?

Why on earth would she do that?

Absolutely not

OP…couldn’t you sleep on sofa downstairs and give them your bedroom?

Ha ha. That's what would be said if this was OP's stepchild!

So it's op's dh who should be sleeping on the sofa, being the step parent.....

No way in hell should either of the people who actually pay the bills consider giving up their rooms to this pair. That's before you take into account their health issues.

As Margaret Thatcher once said, 'No. No. No.'

You have to be joking! She has to be uncomfortable, and take a tiny amount from them for rent /, keep! Perhaps she ought to sleep in a tent in the garden!

Don’t be held hostage by a decision they made without consulting you. You and your DH are doing the right thing by saying no this time. Your son and DIL are being total CF’s about this

Ha ha. That's what would be said if this was OP's stepchild!

OP…couldn’t you sleep on sofa downstairs and give them your bedroom?

So rude and presumptuous of them. Living in garage is crazy and is it even legal or safe.

YANBU.
Don't do it.

Don't make excuses about why they can't move in Op, just tell them you and your DH don't agree to this. Once they live with you it's a done deal with no timeline, if they can't find work, house prices go up, or they just don't save their money you could end up with them for years.
He's your DS so it's difficult to tell him No but in a couple of years with them there your relationship with him could be in pieces

Incredibly rude and presumptuous. I would absolutely shut down this idea immediately before they leave their jobs. Stand firm and let them know today that this will not be happening 😳

they need to hear the words “welcome to adulthood” the can’t just go back to mummy and daddy when things don’t go their way

“No, sorry, that just won’t work for us, we don’t have the space and can’t afford to provide for 2 adults who are not working. DS, if you are ever really struggling, of course we would help you out but your GF, as much as we like her, is not our responsibility.”

No is a word and you need to be standing by this decision @OneFunnyPearlTurtle
I haven't voted because you are unreasonable to be even considering your DS and his GF moving in because you want to help them! The best support you can give is to let them stay in their jobs and support themselves.

Obviously you are not unreasonable to say no to someone trying to tell you they'll be moving into your house, whoever that someone is. If you wanted to help then could you offer your garage as storage, if it's big enough for someone to consider living in? That way you don't suddenly double the size of your household with two freeloaders but are offering practical help towards them buying somewhere.

What if she gets pregnant living with you and they're both jobless?

I would tell them it's an interesting idea but it does not work for me, so no thank you.
It would be better for you op if you had shut them down when they first proposed this, but that doesn't mean you have to obey them now.

I done this, but with kids. We moved back to my parents for two years whilst we waited for a house to be built and to save, however we had these conversations properly before hand and we paid my parents much much more rent.

We sold pretty much everything in our rented house pretty much so had nothing to take, otherwise we would have had the storage issue also.

It may be easier as they don’t have children if you did agree to it but let me tell you it was hard and stressful! I’m not sure I could do it again but I’m forever grateful we had the choice!