Struggling with big baby!

[MommaBee97]

I have three DC, 6 years, 2 years and 4 months old. My youngest was a very big baby weighing 11lb2oz now he's 4 months old he's weighing a little less than 20lb, 4lb off my 2 year old anyway, I currently live in a first floor flat which I am trying to get out of, however it's beginning to be a struggle going up and down the stairs. My baby is too big and heavy to go in a car seat, but my 2 year old needs assisting going down the stairs. Does anybody have any suggestions how to make this easier. I've got to buy a birth to 4 years car seat and the carry carseat is just so hard to carry now. Please help, its beginning to make me not want to venture out to house!

A wrap sling would benefit you hugely.

Definitely a sling. A connecta is a lovely simple solution and safe for baby this size.

A sling. Something like the ergo adapt you can use for both 4 month old or 2 year old if needed

Sling or backpack thingy (though I don't know what the minimum age is for the latter).

Yep, sling. And he will feel lighter in it. We tried a couple then settled on the connecta and never looked back, we used it until he was.... Almost 3 I think.
My DS was 10lb 2 so not quite as big but he was unexpectedly big for us. I was on the first floor at first and couldn't manage to fold our pram down, it was a nightmare, even without a 2 year old in tow. I did go out less. Would be good if you could avoid that option!

After first few months we hardly ever did that thing where you carry the car seat in and out of the house, it was just too heavy. I know people who did it for ages but now realise, they had v light children.

Later on for round the house I tried a hippychick seat briefly www.hippychick.com/products/hippychick-hipseat (got mine on ebay), maybe your 2yo would be able to sit on one to relieve some of their weight a bit if / when you're having to carry both?