paying 2nd home stamp duty

Are you tenants in common or joint tenants - this may be a factor.
But simply put the council cannot consider an asset that is not solely owned by the people concerned, so your parents are correct, the council would not be able to force a sale for fees. It also wouldn't be considered as a deprivation of assets depending on the timeframes.
You really need to get someone professional to look at it though as your portion of your parents house would be subject to CGT as it isn't your primary residence. Obviously the higher stamp duty would be due as even though it will be your primary residence you own another property & you didn't pay higher stamp duty on that.
You need someone to work through the figures properly to work through the route with the best legal outcome financially

See this is where I think she needs advice because my ILs own about 4 rental properties as well as their own so I think she will need to pay the extra stamp when she’s buys her first main residence but then she can prove it’s her main residence so she won’t need to pay extra stamp when she comes to move! It’s only on ‘second homes, rentals’ I think you pay the extra stamp on. I don’t believe everyone that owns more than 1 property has to pay extra stamp on their main home each time they move! But I’m not an expert! My ILs didn’t when they bout their £2m new primary residence and this second stamp issue had come into play the I think as it was 9 years ago.

Having just read @incognito119's post weigh up the 5% additional stamp duty now vs eventual CGT which is much higher.

A long time ago but yes DGP gifted half the property to DM to avoid the possibility of it all going in care costs (there's a much bigger background to why but they had all made sacrifices to be able to own a home so feelings were the buggers weren't going to take it all having not been given help when it was needed).

Is there anyone else who will inherit if care costs don't take whatever proportion of the home you don't own? If it's just you/your children who stand to benefit in the long run I would just accept there's a price to pay now but if someone else is going to get an equal share of inheritance without the additional costs now I would probably try and look at what options there are to reduce the added expense now which they wouldn't have.

Remember this isn't necessarily a one time cost, if you need or want to sell/buy in the future you'll have the same issue if the additional property charge is still in place.

You need to see what the wording of how you own the property is! I’m not a solicitor but I own a rental property, gifted by my parents, jointly with my sister and the solicitor has us down in a certain way. Can’t remember what it is but we are 50/50. Of course this doesn’t impact me like you as I already owned my primary residence. But I wonder if for mortgage purposes you are currently down as all owning a 3rd? This milestone of you purchasing your own property might be a good rationale for you getting a solicitor involved involved in setting out the ownership as 90% you and 5% each parent (my in laws have this as MIL pays very high tax so they have my FIL as 95% owner of rental house so that most of the rental money goes against him for income tax purposes) or even gifting you the remainder of the house. They scrutinise finances for care costs and there does need to be a rationale before likely care costs are due so it doesn’t look like they gave away to avoid care costs (so make sure in any correspondence with a solicitor you say that your rationale is inheritance planning and then giving you more ownership now for having to pay more stamp duty. DO NOT MENTION CARE AVOIDANCE OR CARE!!). It’s great that new government is in and everyone’s been worried that they will reduce the circa £650k allowance so even if their estate is less than that atm you can say that you are worried about the way inheritance tax is going!!). This is something you are legally allowed to do (Tax management). Care avoidance isn’t legal and given the significant costs LPAs are rigorously trying to ensure everyone pays for their own care!

Obviously if they change ownership of their home to you I wouldn’t be getting married as then if you divorce your partner can get half of their home! I don’t think prenups work very well in the UK as you could have gone down that route to remove that problem.

I think if other person does not live their council can force a sale when second one of your parents goes into a home.

Here is the link
www.tax.service.gov.uk/calculate-stamp-duty-land-tax/#!/intro

I did this. I didn’t pay the extra stamp duty as I was buying my makn residence. You can go to the stamp duty calculator on the gov.uk website and it will ask you all the relevant questions. I said I have 2 homes and was buying my main residence and it said I only have to pay normal stamp duty. This was backed up by my solicitor in the house move.
you will have to pay capital gains if you ever sell your parents house

This isn't right. You don't pay CGT if you sell your main property but you do pay second home stamp duty if you already own a property and buy another one.

And the ownership of property doesn't mean its automatically discounted for care costs financial assessment. It's people living in it. The aim of the policy is to enable spouses or dependent children to continue to live in the property.

So if your mum goes into care then your dad is still living in the house and it doesn't count.

If your dad also goes into care, but also he might need care at home, which would be different.

But if he is in care then the house counts as a financial asset. If you own a third, then that third wouldn't count. But the other two thirds would. So highly unlikely that your third would make the difference in not needing to contribute, unless the house is very cheap.

So you are balancing a hypothetical situation about situations which may or may not happen.

Against an absolute certainty that you will need to pay higher rate stamp duty which you can calculate exactly what that will cost you

You need proper legal advice to understand your position in relation to your parents house.

Are you a guarantor?

Do you own a third?

What is the actual situation

I agree with others that you need to get proper legal advice, but on the face of it it seems unlikely that your being on the deeds would "protect" the property if both parents needed care in the future.

Residential property is disregarded if a spouse or partner, or dependent adult is living in the house. The purpose of this is to ensure that no-one is made homeless because one of the adults in the house needs care. As you don't live in the house, that wouldn't apply.

Also, trying to hide or transfer assets to avoid nursing home fees is usually a fool's errand as many local authorities put considerable effort and resources into tracking down assets, and in any event, if you are a self-funder you have more choice about the location and type of care you receive.

You haven't fiddled the system but now the original issue has been resolved you won't get away with it for other purposes.

Councils actively pursue for care costs whether that is immediately or a claim when the house is sold

I was added to the mortgage by broker

Are you actually a joint owner of your parents’ house or are you just a guarantor?

As pp say you really need some proper legal advice.

I think you'd have to be a dependent adult living in it for that to apply. Otherwise care home fee avoidance would be too easy.

You need proper professional advice. Not the views of a load of randoms on the internet.

My understanding is that second home stamp duty isn’t payable on your main residence. So if you’re buying a place to live in, full time, yourself, it may not be applicable. IANAL though. The second home stamp duty was for additional homes - like a weekend house or a BTL.

(I agree with PPs that speaking to a solicitor would be wise and well worth the money)

If they are also on the deeds to the house then you being there too won’t stop it from being subject to a local authority claim for care costs. It might mean that each parent’s share is only considered to be a third rather than a half, but your parents’ shares will still be factored in to the local authority’s financial assessment.

I also don’t think it’s fair for you to have to pay thousands in stamp duty because you agreed to help out your parents. Would they be willing to pay or partially pay the additional stamp duty?

You've asked about this before.

You need legal advice on best course of action. See an solicitor. It will be a couple of hundred quid well spent