Should mum pay for the granny annexe?

I agree. We have just done this for my dm and never crossed our minds to charge her rent or make her pay.

If you work will your DM be on her own most of the day? Will she know anyone apart from you?

How will you cope if she needs more care and support?

Would it be better if she moved into retirement property near you? Then she would gain a social circle

I don't think OPs mother is doing anything to her it was OPs idea.
It isn't something everyone would want and I wouldn't but I know someone who has done this and it has worked very well. It all depends on the individuals involved.
If you can afford it I think PPs ideas that you pay for the extension and then you charge rent makes the most sense. Although I think your idea of having some of your inheritance early to pay for the extension also sounds reasonable.
But I think thank you need to talk to your mother to come to an arrangement that suits you all.

Maybe your mum won’t want this. You’d be surprised, OP. I sure was!

I was in a similar situation years ago. My mum didn’t want to live with us. She preferred staying in her own home which now funds her nursing home. It’s so much better! My mum ended up with dementia and I wouldn’t have coped with the care she’s required in her 80s. It would have been too big for me. I’m happy to see ‘my inheritance’ (her money) supporting her in her old age. That’s what her money is for. She’s ended up in a great home being really well looked after and it’s taken a huge burden off of me (I’ve been in a carer role before and it can be really tough on everyone in a household). The 80s can be, not always, but can be- just want to clarify so that I don’t get hate- a tough decade, i.e. big steps downward rather than a steady decline.

To counteract all the doom and gloom

I wish people wouldn't make comments like this. People are only giving their own experiences and speaking about how providing elderly care has impacted them. It's great that you had a positive experience but it's not being "all doom and gloom" to speak about the other side of it.

Mum was Nanas only child though so no-one to disagree with

To counteract all the doom and gloom a happier story:

My much loved nana lived in an annexe to my parents house for I think about 5 years before her death and it worked really well. She paid for the renovation I am pretty sure from savings and rented out her own home. She contributed to the bills as she liked to pay her way. She loved her little flat. She was pretty independent but could share meals etc with my parents as often as they both wanted. She was still compos mentis although quite frail and she didn't need any personal care. My mum used to go in to say goodnight to her every night and take her a cup of tea in the mornings and then one morning found she had died peacefully in her sleep (she was in her late 80s). It was exactly how she would have wanted to go.

It was a lovely arrangement for all of them.
Nana had helped a lot with us kids when we were small driving us to school and doing afterschool care and regular babysitting and she got on well with both my parents so it was no hardship to them to have her live with them.

In some ways it's easier (less travel and more opportunity to visit) but in many ways it's harder too - because you're round the corner, you're the one expected to be there all the time. To drop your plans because mum has had a fall, or is confused, or because the carer can't get there so you need to go and make sure she's taken her medication or eaten her dinner (or one million other things).

We're dealing with this at the moment and it's incredibly stressful - even with a big family to share the load around. I can't imagine doing it all alone.

You need expert advice on this one. A disagreement on this, and subsequent inheritance implications, is that reason my mum no longer talks to her siblings.

Expect the work to cost a lot more than the value added to the house. Hopefully less so in your case because you already have the guts of it done, but important to bear in mind all the same. Get some valuations done and distribute them round the family so everyone understands you are not making a mint off your mum's "investment" in your house. It's not an investment, it will be mainly just a sunk cost that someone will have to bear. Her paying in exchange for living in your existing space "rent free* might be reasonable but don't assume that it will be seen as such by others.

You also need proper advice on bills and in particular council tax. IIRC if the spaces connect internally it's still one property for council tax purposes, but you need a better source than MN. Be extremely careful.

This is so true. You don't need to be particularly high needs to need substantial levels of care in your final months - my experience is that people can function well for considerable periods, but once they start deteriorating, they can go from "frail but functioning" to "need 24/7 care" incredibly quickly.

If they're living with family members, those people will be expected to step in and provide that care, and it can destroy families and cause huge amounts of untold stress and upset.

Elderly care is about so much more than maybe going in to a care home.

Of course it is. I was referring to posters who ask what will happen when DM needs to pay for a care home.

There can be lots of challenging and distressing aspects of caring for an ageing parent. I would think these were easier to cope with if the parent were nearby and you could support them.

I fended off this suggestion from my DM.
DSis1 wanted to move in with her, effectively becoming a sitting tenant in her paid-off house, despite DM not liking her DH or DC.
DSis2 wanted her to sell up and give her the money to buy a much bigger house, despite not getting on with DM(!)
I didn’t want to take her money to enable her to move in, as it wouldn’t be fair on my siblings, and I wouldn’t have wanted to extend my house, so I suggested she downsized and moved nearer us and DSis2 instead, so we would both be available to help her, (although DSis2 wouldn’t do anything practical, in the event: that was mostly left to me - as in visits, meals, shopping, theatre visits etc.)...
She followed my advice, and as her health deteriorated in later life, we sold the downsized property to pay for her care, leaving what remained, to us equally, as per her Will, when she passed away, and effectively stopping any sibling from gaining an advantage over the other two!

People are talking from experience.
Lots of elderly don't go into care homes because their family are on their knees caring for them.

MN love to catastrophise about old age but only a small % of people go into care homes.

It's catastrophising to speak about your own personal experience and how challenging it can be. Elderly care is about so much more than maybe going in to a care home.

I hadn’t realised paying to adapt a space belonging to a child make it usable for you would also be considered deprivation of assets.

I doubt it would be. People seem to have got the wrong idea about what actually constitutes deprivation of assets.

If OP's mum pays for building works which are going to benefit her i.e. provide somewhere for her to live, then it wouldn't be viewed as intentional doa.

OP - I'd go 50/50 on the building work.

MN love to catastrophise about old age but only a small % of people go into care homes. There may be challenging times ahead but how good is it that she'll be on your doorstep and you won't have to do 400 mile round trip dashes to her in an emergency.

And how lovely DM will grow older and die close to the daughter she loves and raised.

All the best, OP.

I think there's a very real possibility that you'll spend a lot of money on something that your mum ends up not being able to use - or that she'll only use for a matter of weeks or months before her needs are too great.

I absolutely hate to sound so negative but we're going through similar with a family member at the moment and her needs have gone from "independent and able to live at home" to "palliative care in a home" in a matter of weeks. Things can change so quickly at those ages.

While your plan sounds wonderful on paper, I do think you need to think about the possibility that your mum won't be independent enough to live in an annexe by the time it's completed.

Are you likely to stay in your area for the duration of the rest of her life? Are you in a cheaper area of the country? If so, how about she sells her (expensive) place and buys something smaller near you. (And tell your siblings to help with the move. It's the least they can do!)

I would orgsnise a family meeting and ger input from your mother and siblings.
Don't be the go to sibling/daughter. As your.mother ages her needs will increase. She may be fine now but remember this is the best she will be, it's downhill from now.

I don't mean to be a negative nelly but I'm speaking from experience.Caring for an elderly person is a huge undertaking. While rewarding it can have a huge impact, physically, emotionally and financially on you, your DH, children etc..

Please think long and hard about what's best foe not just your parent but your family too.

we did this for my mum after a sudden and severe stroke left her unable to be independent at a relatively young age (70) . we paid for the building work as it added value to our property but she paid for some of the specific internal modifications she needed which we wouldn’t otherwise require ( low level work tops and special shower unit etc) she also
pays us rent to cover food and bills.
however, please also do be aware that although this mostly works very well for us and i do enjoy having my mum so close by , it is an enormous undertaking. the emotional
and mental load on the rest of the family cannot be underestimated and with time, her needs increase. please do consider how this will impact your family in the long term.

The agreement we had for my MIL was that she paid for the work (from her house sale) to be done for the granny annex but didn't pay any rent afterwards. Our house was worth more afterwards, but everyone agreed we wouldn't be getting the work done if not to help her. So it was not unreasonable. Her sister complained we were being unfair and I suggested she could go live with her if she preferred and the complaint quickly went away! MIL was utterly thrilled to be with the grandchildren and definitely didn't feel taken advantage of at all. She had carers but we also provided care until she died. You will be default the carers but that was true for us anyway, it just made it easier for me/DH to do the caring because she was right there, no driving an hour to sort something out.

I think this has trouble written all over it. We had a relative do this, they paid a lot of money for the annexe and then a few years later the couple split and the elderly parents are now living a very different life to what they would have had if they had not lost their money in the annexe. Partly I’m sure due to naivety and not getting decent legal help but I still think it has too many risks from both sides. I’d either fund it totally or perhaps your mum would like to give each child a lump sum now? Risky for her though.

Can't you discuss this with your siblings and mum?

I'd see what they thought was fair and then decide whether I thought their proposals seemed fine with me and go ahead, or not, on that basis.

This. ↑↑

Not ina million years.

What is mum went into care for years?

Therefore, as most FM's have stated, you pay for it as its your property and the annex/extension is part of that that will increase the price of your place

No way should mum pay for it and get stuck there, ie lets say she changed her mind and wanted to move - its easy to move if you are paying rent.

So, you pay for the extension to your home and let mum do what she wants with her money