Beam and block floors

[Chojin]

I'm investigating the feasibility of retrofitting beam and block flooring into my end of terrace victorian house if anyone has any experience please.

The reasons for thinking of beam and block is that they supposedly have a more solid feel. I would also like to fit insulation and underfloor heating and think it will help with the thermal mass. I'd rather keep the void so have discounted a solid concrete floor.

The thing I'm not sure about is how the beams need to be suspended. Would the existing (solid) wall be strong enough to hold them, or would a sleeper wall be required? Who would be best to contact, would a structural engineer give me a definitive answer on this, the strength of my foundations etc?

I'm also looking to get the loft converted in future with underfloor heating, and was considering hollow core planks for the flooring. Again that would add to the load of the house which I would like to address before going ahead with anything.

I'd be interested to know of anyone's experience with this construction method and thoughts on it compared to suspended timber.

 

[the_r_sole]

Really, that's a hugely difficult thing you are trying to achieve there!
You would have to build new foundation walls, so a fair bit of careful digging required around existing services etc, then trying to manouver the beams around inside a house.
You couldn't really fix into the existing walls with them - solid floor would be the easiest way to achieve a more solid feel, why have you discounted that?
Also, hollow core for a loft conversion?!?
IMO you would be much better buying a house constructed the way you want rather than trying to retrofit a different construction method - unless you are absolutely loaded! Might even be cheaper to level your house and start again than trying to change the ground floor and midfloor/roof construction

 

[Chojin]

I'm not loaded but my house is a fixer upper so I did buy with the intention of some serious work rather than just a lick of paint

The ground floor will be about 12m x 5.2m in total including a kitchen extension that I will be doing. I'm planning on moving out while the work is done so don't mind my house turning into a complete building site.

Current issues I have are that the floor in the two receptions rooms is very bouncy. It looks like the timber joists have been bodged in places too. The copper pipes run along the top of the joists and make a knocking everywhere - drives you nuts! The radiators are ancient anyway so it would be a good opportunity to get some wall space back and go with underfloor heating.

I'd like to fix those issues and feel I can kill a few birds with one stone. I also thought it would be good to have the same subfloor for both the new kitchen and reception rooms.

I've read a few scare stories about solid concrete in victorian houses causing dampness issues so would prefer to keep the foundations ventilated.

The cost of the beams and blocks doesn't seem too bad. I priced up £2k for those for the ground floor, but as you say the foundations would need work and are a bit of an unknown at the moment. Access might not be too bad via the back of the house while the kitchen is being extended.

 

[Maccapacca]

You'll still need to screed over the top of beam and block. Sounds like a massive PITA to me. I'd tear it all out lay a concrete floor then insulate then screed. Even then you may have problems with ground heave. Surely just getting what you've got renewed or repaired properly is cheapest and best.

Your cost for the beam and block I assume don't include any labour.

 

[ANDARIAL]

I've read a few scare stories about solid concrete

Not if done properly with DPM and kingspan insulation

Can you get a builder involved to give you some advice?

 

[the_r_sole]

You are basically building a complete new build floor inside of an existing foundation, move/alter your services etc.
Material wise what have you allowed for new foundation walls? A few concrete pours? How's the access for any small machinery or are you going to hand dig/barrow material in?
Will you have any access into the solum for fixing any pipework etc below there?
I really think you are making a very expensive, problematic solution to a problem that isn't really a problem!

 

[Abyss]

Current issues I have are that the floor in the two receptions rooms is very bouncy. It looks like the timber joists have been bodged in places too. The copper pipes run along the top of the joists and make a knocking everywhere - drives you nuts! The radiators are ancient anyway so it would be a good opportunity to get some wall space back and go with underfloor heating.

Sounds like a complete overkill solution. I would replace the damaged joists, install additional noggins/joists to further reduce the bounce, then fit something like 25mm ply on top. If you put in enough noggins and overlay 25mm ply you should have a very solid floor.

In terms of the pipework whilst the floor is up it will give you the opportunity to cure this by ensuring the cut outs in the joists are big enough and that they are properly supported and felt or similar around them to prevent the knocking sound.

 

[Chojin]

You'll still need to screed over the top of beam and block. Sounds like a massive PITA to me. I'd tear it all out lay a concrete floor then insulate then screed. Even then you may have problems with ground heave. Surely just getting what you've got renewed or repaired properly is cheapest and best.

Your cost for the beam and block I assume don't include any labour.

That's right, that was just the cost of the raw materials for the beams and blocks. Insulation, screed and labour would be required whichever method I go for. I would expect any time saved on deploying the blocks will be taken up with preparing the beams.

I had read about ground heave with solid floors so that's another mark against it.

I was initially thinking of just repairing what I've got but there are so many interconnected items that need doing that I don't mind going for something more drastic (whatever that is), and knowing that once I've got the place nicely furnished it's not all sitting on a pile of old wood. PITA I can deal with, but obviously it does need to be economically viable.

Not if done properly with DPM and kingspan insulation

Can you get a builder involved to give you some advice?

What kind of DPM would you suggest? Something that can protect against damp and radon I assume. Getting people around to discuss work is a bit tricky for me at the moment as I'm at work all day and will probably have to wait until I'm on holiday around autumn time.

You are basically building a complete new build floor inside of an existing foundation, move/alter your services etc.
Material wise what have you allowed for new foundation walls? A few concrete pours? How's the access for any small machinery or are you going to hand dig/barrow material in?
Will you have any access into the solum for fixing any pipework etc below there?
I really think you are making a very expensive, problematic solution to a problem that isn't really a problem!

All my services enter and exit at the back of the house which will be already getting disrupted during the kitchen extension. The only thing would be the Virgin connection which I don't mind losing, or specifying during the overhaul. I don't know what other pipes would be around there. There would be electrics but that needs sorting anyway during my renovation. Access should be possible once the rear reception room window is knocked open and the floor boards and joists are removed. It could be used for machinery and/or barrow.

Material wise I'm not too sure on quantities, that might be where a structural engineer comes in. There is the trench foundation option, but then I was also wondering about mini piling solutions which could support the concrete beams (and not need to be strong enough to hold walls and roof).

Sounds like a complete overkill solution. I would replace the damaged joists, install additional noggins/joists to further reduce the bounce, then fit something like 25mm ply on top. If you put in enough noggins and overlay 25mm ply you should have a very solid floor.

In terms of the pipework whilst the floor is up it will give you the opportunity to cure this by ensuring the cut outs in the joists are big enough and that they are properly supported and felt or similar around them to prevent the knocking sound.

In theory that does seem like a good low cost solution. A friend of mine had a couple of joists repaired, what seemed like a simple repair job cost over £1000 - so in theory I would also be left with a wooden floor which doesn't seem to suit underfloor heating. There are systems out there that claim to work with wooden floors, but I'm not sure how well as a complete replacement for radiators for example.

 

[the_r_sole]

How much have you got to spend on this?
Get a builder around to give you a quote and see if it's anywhere near what you are imagining for this job, I can guarantee that it's going to be more expensive than you think.
It's a huge amount of work with a lot of potential problems and costs for very little
Mini piles are even more expensive and require machinery you would also have to make sure there is absolutely nothing in ground like drainage runs etc which aren't always obvious in older properties.
It seems like you don't really want to listen to anyones advice on here so the only thing you can do is get a builder around to price it, then you will understand if it's viable or not (it's not btw) unless you aren't worried about the ceiling price of the house or potential resale values - all so that the floor feels "a bit more solid"

 

[Chojin]

It seems like you don't really want to listen to anyones advice on here

Not true, I'm taking it all on board, but still like the beam and block idea. A third of the ground floor will be taken up by the new kitchen so I still need a solution for that regardless of if the rest of the house is patched up or something more substantial is done. Over the next couple of years I don't want to spend more than around £80k on the house - for the kitchen, loft and anything else that needs doing. I will get some builders around once I get planning permission for the rest of my work.

 

[the_r_sole]

Not true, I'm taking it all on board, but still like the beam and block idea.

So everyone telling you it's a bad idea and not very viable, but you still like the idea, is you listening to the advice?!
You only still like the idea because you don't understand either the complexity or costs involved in retrofitting a different construction type on an independent foundation within an existing (and old) building footprint.

 

[Chojin]

So everyone telling you it's a bad idea and not very viable, but you still like the idea, is you listening to the advice?!
You only still like the idea because you don't understand either the complexity or costs involved in retrofitting a different construction type on an independent foundation within an existing (and old) building footprint.

Maybe so, but I'm also not credulous enough just nod my head to every piece of info that comes my way either. I wouldn't have asked people on this forum if I didn't want their opinions.

 

[Abyss]

In theory that does seem like a good low cost solution. A friend of mine had a couple of joists repaired, what seemed like a simple repair job cost over £1000 - so in theory I would also be left with a wooden floor which doesn't seem to suit underfloor heating. There are systems out there that claim to work with wooden floors, but I'm not sure how well as a complete replacement for radiators for example.

It depends on your perception of low cost. If £1k isn't a low cost solution to you then I certainly wouldn't be looking at your original solution. I am no QS but what you are talking about could potentially run into tens of thousands of pounds.

 

[ash_91]

just put new timber joists in, beefier than whats already there, all the victorian houses ive worked in have had undersized joists.

You can put a full wet underfloor heating system in with joists aswell, fix a batton to the side of the joist, fit celotex inbetween, lay pipes and screed to top of joist.
works well, done it loads of times.

 

[aussie reno]

I think it sounds like a great idea!
I’m a former structural engineer now working in development. I would imagine that on the party wall, at least, you might be best served building a dwarf wall on a strip footing and allowing the beams to cantilever over if you can. This will avoid any party wall agreements. You would also want an internal support at midspan (across the 5.2m span) to reduce any vibration effects.
I’m thinking of doing the same myself in my renovation project. Nothing like using the whole floor as a radiator and I’m a big fan of polished concrete.

As for tens of thousands of pounds..... highly unlikely! All the best with looking at this and please do let me know via PM once you get your costs.

 

[a1ex2001]

We moved our kitchen into what was our dinning room on a Victorian suspended timber floor there was far too much bounce so we added a new beam under the joists at mid point and built a pillar to support the new beam in the middle cost very little as and extra item on the extension we were doing and the floor while not as solid as a concrete one moved very little.

Your 80k budget seems a bit light to me for a total renovation including an extension and loft conversion with presumably a full re-wire, major central heating alteration, new bsthroom(s) and kitchen!

 

[Paul Bandler]

I'm investigating the feasibility of retrofitting beam and block flooring into my end of terrace victorian house if anyone has any experience please.

The reasons for thinking of beam and block is that they supposedly have a more solid feel. I would also like to fit insulation and underfloor heating and think it will help with the thermal mass. I'd rather keep the void so have discounted a solid concrete floor.

The thing I'm not sure about is how the beams need to be suspended. Would the existing (solid) wall be strong enough to hold them, or would a sleeper wall be required? Who would be best to contact, would a structural engineer give me a definitive answer on this, the strength of my foundations etc?

I'm also looking to get the loft converted in future with underfloor heating, and was considering hollow core planks for the flooring. Again that would add to the load of the house which I would like to address before going ahead with anything.

I'd be interested to know of anyone's experience with this construction method and thoughts on it compared to suspended timber.

I found this thread while searching the internet for information on replacing timber floors with beam and block. So just interested to know if you went ahead and have any further insight on the approach? I have a similar challenge in renovating and converting an old (1930's) church hall into a residence that is a similar dimension to that indicated above. The old timber floor is rotten and am concerned that replacing with a solid concrete floor could push moisture our to and up the walls. I doubt the walls have a proper DPC, and chemical injection is never fully successful, so am attracted to the idea of retaining the vented void under the (quite high) floor.

 

[Chojin]

I think it sounds like a great idea!
I’m a former structural engineer now working in development. I would imagine that on the party wall, at least, you might be best served building a dwarf wall on a strip footing and allowing the beams to cantilever over if you can. This will avoid any party wall agreements. You would also want an internal support at midspan (across the 5.2m span) to reduce any vibration effects.
I’m thinking of doing the same myself in my renovation project. Nothing like using the whole floor as a radiator and I’m a big fan of polished concrete.

As for tens of thousands of pounds..... highly unlikely! All the best with looking at this and please do let me know via PM once you get your costs.

I found this thread while searching the internet for information on replacing timber floors with beam and block. So just interested to know if you went ahead and have any further insight on the approach? I have a similar challenge in renovating and converting an old (1930's) church hall into a residence that is a similar dimension to that indicated above. The old timber floor is rotten and am concerned that replacing with a solid concrete floor could push moisture our to and up the walls. I doubt the walls have a proper DPC, and chemical injection is never fully successful, so am attracted to the idea of retaining the vented void under the (quite high) floor.

It's good to see other people looking into a similar thing. I have got so far as to employ an architect and structural engineer, both who said while unusual, any competent builder would be able to do it. The structural engineer has proposed having a new 'overpin' foundation that wraps over the existing strip footing foundation. Then 7nm blockwork sitting on the overpin against the external wall, to support the concrete beams.

I still need to go through the party wall notice but as I'm getting other work done to the property, I'm going need it anyway. So nothing built yet... but hopefully next year! It would be great to hear how you get on with your own project.

 

[Pwpw]

Resurrecting the thread. I'm considering replacing a suspended ground floor with beam and block. @Chojin did you go ahead

The house is a dilapidated Victorian mid-terrace. The main section is 5x8m WxD and a kitchen off the back of 3x7m. We will wrap around the kitchen, extending it to 5x10m total, and likely spec beam and block for that new floor. Whilst there are no damp problems now I don't want to take any chances.

We will be insulating extensively and fitting an air source heat pump. Underfloor heating is therefore key. Plenty of UFH impregnated chipboard/ply subfloor solutions exist to lay over existing joists but I wouldn't be surprised if B&B + screed will give better performance per price. Interested to hear any thoughts.