Radiator pipes too small, so house never warm enough.

[Curlingstone]

I've got decent radiators ( should be more than enough BTU for the room) but ridiculously small pipes leading into & out of rads. Everything in this house was done on the cheap by previous owners.
I had new boiler fitted 4 or 5 years ago.
Does this mean the pipes under the floor are also likely to be small guage? Would replacing be feasible? How disruptive/expensive?? The thought of ripping up all the floorboards fills me with dread. It's taken me 8 years to get the house even remotely up to scratch.
( Yes if I'd realised/ been advised better I would have done this 8 yrs ago)
Any experience or advice would be most welcome, thanks

I'm getting quotes atm for a refit of rads, new boiler etc. The smaller pipes, according to the last plumber, are common in more recent builds (mine is early 2000's) and not a problem if the flow rate from the boiler is set correctly. No one has suggested I need new pipes.

My house is warm and the rads are clearly coping - I'm just switching to a combo boiler, taking out the hot water tank and reconfiguring the space and redecorating.

Maybe your system just needs flushing? In my old house we had a big magnet type thing off the boiler that captured gunk.

Thanks @TheOnlyKoiInAPondOfGoldfish that sounds reassuring & something I can investigate. The house is Edwardian but judging by bathroom & kitchen style probably had the last reno around 25 yrs ago, so that fits re pipe size.
Off to Google flushing boilers!

Our house also has the 'microbore' pipes but with a decent boiler it's fine. The last radiator on the circuit is in quite a big room though so that room sometimes feels a bit cooler.
We had a new boiler about 3 years ago and they put a magnetic sludge trap in which stops the pipes furring up over time.

Does this mean the pipes under the floor are also likely to be small guage?

Sounds like microbore pipes to the radiators. Depends on how the system was designed if the whole system uses this size.

Parents have microbore pipes to the radiators, but the rest of the system underfloor isn't. My dad put it in years ago and did some funky stuff under the floor with manifolds. God knows what, but it's never cold there.

Funky stuff with manifolds 😂@HelpMeGetThrough
Will investigate under floorboards when next opportunity arises.
Sounds like I need to desludge the boiler first/ check for magnetic trap.
Thanks all, these replies v helpful

New systems are common having microbore. If the system is clean and no blockages then it should be fine. However, we are staying in our current house for ever so the plumber advised to have conventional piping so less susceptible to clogging etc, even though DH is neurotic about system additives and having them topped up yearly etc

Our house was built in the 80’s. In 2021 we decided to upgrade the radiators. The chap doing it said at the time that it would be best to upgrade the pipes at the same time. He put in larger pipes and the difference it made is amazing!
I won’t lie, it was a huge upheaval at the time, took about a week and they had to lift carpet in each room to access under floor, but everything was put back and left in perfect condition. I’m glad we went for that option obviously.
I think it added around £1k to the quoted price, and the job was actually much harder for them than they anticipated due to the way the house was built.

DH is neurotic about system additives and having them topped up yearly etc

Do t blame him. Have you ever seen the contents of an old radiator, it looks like the morning after a night on the curry!! 🤮

It may be that if the previous owners didn't use inhibitor, deposits may have built up on the inside of the pipes. Best to use something like x400 to decalcify and desludge the system as per the forum thread below. Other than replacing the pump with a more powerful one or getting a plumber in to fit one if there isn't one, it's pipe upgrade I'm afraid.
www.diynot.com/diy/threads/additives-to-central-heating-system-to-remove-sludge-scale.310980/

You'll likely have a 22mm flow and return pipe under the floor, a manifold is just a reducer to multiple 10mm (or 8mm though less commonly now) that run to radiators.

There are problems with 8mm getting sludged up so treating the system is important but shouldn't need to be changed. 10mm is less problematic

@Surplus2requirements that's encouraging about pipes under floor. I definitely need to desludge, add inhibitor etc. Had an ' incident ' last week while bathroom being redone involving water pouring out of an uncapped radiator 😠

Posted too soon. So may have done a DIY flush! Any inhibitor in there will have been washed out ( and into my kitchen ceiling 😭)