Issues with replaced joists

[Brammers]

Good afternoon everyone,

 

I hope you are enjoying the bank holiday weekend!

 

I'm new here, I've had a look around and I can't see a topic on the issue I have (which I guess is a good thing!).

There is a bit of a backstory here so please do bear with me.

I moved into my house coming up to 4 years ago, there was a wall in the kitchen that didn't make much sense in being there so I spoke with a (former) friend who I knew as a builder, he came round and had a look and noticed that above one of the walls I wanted to remove, there had been 3 (partly) replaced joists that were held together with a few wood screws, he advised me that I needed to put 2 x 12mm coach bolts through each them and then I'll be ok to remove the wall below.

So that's what me and my old man did one weekend, there was a pillar which was part of an old wall which I left in as I liked it as a feature, (this was 3 years ago) the wall got removed bit by bit with no issues.

Fast forward to last week (W/B 25/04/22), I want to remove the pillar now to fully open up the kitchen and the remaining wall that formed a breakfast bar.

I wanted to get a builder in to confirm that I was able to remove the pillar with no issues and that's when everything seemed to snowball!

I spoke to one builder (Monday, last week) and he asked me to send over some pictures and he'll let me know when he would be able to get out to have a look.

Tuesday afternoon rolls around and I get a phone call saying he thinks I'll need a structural engineer, he gave me the number of a mate of his, I then spoke with him, he thinks I'll need an RSJ, I want to avoid this where possible as it'll have to be a 7m to reach side to side of my kitchen.

I've been Googling (as you do to try and learn about the issue) and found that I might be able to replace the joists as the span is 3200mm (ish) using C24 47x175mm timber, I spoke to the structural engineer and he seems adamant that I'll need an RSJ (he hasn't been around to look yet)

I looked at the average price of a 5m RSJ supplied and fitted and it seems to be just over £1k, not something I was expecting and not something I can “just pay for” either.

 

So, after all that, my question is, can I not just replace the joists so that they sit wall to wall? I understand it’s a floor boards up, wiring out and ceiling down etc but I’d prefer to do that than have a 7m RSJ in my kitchen.

I put the acro's in as a "just in case" it's been fine for the last 3 years.

 

Any advice is much appreciated

[ProDave]

It is unclear where the upstairs floorboard up picture relates to the downstairs pictures, but the upstairs picture shows the ends of 2 separate joists bolted together.  That MUST be supported below that bolted joint either by a wall or an RSJ

[ToughButterCup]

Hello @Brammers. Please try not to think of us as experts: we're just hard-bitten, nosey folk with a smattering of this that and the other as far as building is concerned. (Apart from @nod)

 

My fingertips are fizzing with caution. Please get an SE to come round and give you an opinion. Please. You might just be right in doing it your way, but .... 

[Mr Punter]

Yes, definitely have a structural engineer design the solution for this.

[saveasteading]

You can replace joists like for like if they are performing as joists, ie only supporting their own narrow area of floor.

 

BUT you cannot have that size of timber supporting joists that run the other direction.

 

Could you sketch or describe in detail what you have, including where the bolted joints are?

 

My hunch is as above, that you will need an rsj or a wall....but send us the info to make sure.

 

 

 

[Temp]

+1 to insufficient information to determine if an RSJ is needed.

 

_If_ that wall was only supporting the middle of some floor joists that span 3.2m then it does look like replacing them with 44/47 * 175 C24 would be OK.

 

However walls and pillars frequently perform other functions. I would pay an SE to come take a quick look. The one you spoke to might be under the impression this wall was once an external wall and you're knocking through into an extension or something like that. 

 

[saveasteading]

4 hours ago, Temp said:

might be under the impression

A lot of scary alterations have been done without permission or proper knowledge, and I suspect BCOs and SEs see a lot of them. 

Yours may well be fine.   If so then the fee will not be great. If not then it does need expertise and sorting.

[Brammers]

Good evening all,

 

Thank you for your replies and sorry mine is late!

 

I do plan on getting a builder out but they don't seem to be very forthcoming.

In regards the the floor joists, the "new" sections are 1900mm in lenth, they are supporting a false wall (I can't think of the proper name).

On 02/05/2022 at 15:48, ProDave said:

It is unclear where the upstairs floorboard up picture relates to the downstairs pictures, but the upstairs picture shows the ends of 2 separate joists bolted together.  That MUST be supported below that bolted joint either by a wall or an RSJ

Where the pillar is in the kitchen, the last joist on one of the pictures is sat on there and the others are to the left, if the makes sense? I've attached a picture which would hopefully make more sense.

 

On 02/05/2022 at 18:30, saveasteading said:

You can replace joists like for like if they are performing as joists, ie only supporting their own narrow area of floor.

 

BUT you cannot have that size of timber supporting joists that run the other direction.

 

Could you sketch or describe in detail what you have, including where the bolted joints are?

 

My hunch is as above, that you will need an rsj or a wall....but send us the info to make sure.

I'm wondering if I can replace the ones that have already been cut and place them on the walls either side like they would be if it was a new build (at a guess)

I do have a plan of my kitchen when I got my new one designed, I'll make some notes on that and post it here for you to have a look at.

 

On 02/05/2022 at 20:02, Temp said:

However walls and pillars frequently perform other functions. I would pay an SE to come take a quick look. The one you spoke to might be under the impression this wall was once an external wall and you're knocking through into an extension or something like that.

On that note, something I was talking to my neighbours about this and they reminded me, before I bought my house there was a water leak in the bathroom that basically flooded the house, and because it was cold at the time it froze too, I wonder if the 3 joists took the brunt of it and started to rot and that's why they were replaced. Pure guess.

 

On 02/05/2022 at 20:02, Temp said:

However walls and pillars frequently perform other functions. I would pay an SE to come take a quick look. The one you spoke to might be under the impression this wall was once an external wall and you're knocking through into an extension or something like that.

Thank you, I hadn't thought of that. He is due out, hopefully next week to have a look and go from there.

 

Thank you with all your help with this, I do truly appreciate it!

 

John

[ProDave]

As I feared, the two "used to be sat on a wall" are now effectively one joist, spanning a longer distance than they did originally, and with the added complication that there is a joint in that now effectively longer joist.

 

Definitely need a SE to first tell you if that joist section can actually span the longer distance now the intermediate wall has gone, and if so is that joint adequate to do so or does it need some reinforcement.

[Brammers]

Yeah, I realise now that taking that wall out wasn't the best move but when someone you know as a builder says you can... 😕

 

According to some of the building regs (that I found on Google) I've read, if I (or a builder) was to replace a joist and sat it wall to wall, I can use C24 44/47x175mm for the span I'd need.

My ajoining neighbours house is a mirror of mine and they don't have a wall/pillar like I do, without an RSJ so I'm keeping my fingers crossed! (might be the only thing I can do!)

Once I manage to get a builder out, I'll post an update what what they say.

Does it need to be an SE that looks or can it be a builder?

 

John

[Gus Potter]

36 minutes ago, Brammers said:

Does it need to be an SE that looks or can it be a builder?

I would bite the bullet and get an SE in for a look at this. While there are a good few good competant builders out there.. there are less / few that have a true understanding of overall building stability, it's not really their brief so you can't knock them.

 

The main thing is to recognise is that even though you may be looking at the vertical loads you need to hold up, the pillars and even innocuous bits of wall, may be providing horizontal stability to other parts of the building. Often you find walls that don't carry load from above.. non vertical load bearing walls. But these walls are still load bearing walls.. making a major contribution to the walls that are carrying vertical load. They prevent the vertical load bearing walls from buckling and / or to resist the wind loads that want to push your house over like a pack of cards.

 

For all it will cost and in the interests of keeping you all safe, ask an SE. They may even suggest a cheeper way of doing it. If not you will have a correct design that you will be grateful for when you eventually come to sell the house.

 

 

[George]

What was the outcome of this?

 

My thoughts are

- that without seeing it, the SE will say RSJ because that's what is usually needed and no point saying it isn't!

- a single coach bolt just makes a hinge