Beam & Block

[Donwill]

I've been recomended to use an insulated beam and block floor to my proposed single storey flat roof kitchen/dining room extension, the beams being less than 4.2 Metres long. The proposed beams are quite heavy and I(we) will have to carry them some

10Metres and manipulate them in a confined space to place them in position. I understand that, because of the position of the reinforcement within these beams I they can only be lifted at the ends i.e. within 500mm of the ends, I assume that the reinforcement is placed in the bottom section of the beam and to lift them in the middle would put the top of the beam in tension and cause them to crack or break Has anyone had experience of installing these beams and do you have any tips or recomendations to pass on please. Are there any tools or trolleys that can be hired to help with the task? I have a picture in my mind of railway track layers using large pincer type tools having horisontal handles which two men on either side would lift to place the rail in position. Any comments or useful information gratefully received.

Donwill

[Weatherlawyer]

How on earth do you expect an answer on a DIY forum with so little information? Do you think we can read your mind or any of the correspondence sitting on your buraux?

[Donwill]

I would have thought it was obvious to anyone who has actually had experience in installing this type of flooring . If you don't understand what I am asking then clearly you do not have this experience and any contribution you can make is merely guesswork on your part which I am not interested in, thanks but I can make my own guesses, I am looking for informed practical experience. Donwill

[Phil L]

Reccomended isn't the same as being told you have to, you could have a solid concrete floor with insulation underneath or a traditional wooden joist and floorboard floor...TBH most building control officers aren't too interested in what the floor is like and if you inform him that you intend putting a solid floor in he will accept this 99% of the time. The only reason I can think of for having this type of floor is to retain ventilation under the existing house floor which is suspended? - if this is the case, you can put ducting underneath a concrete floor and vents on the outside wall of the extension to retain the existing ventilation.

If you decide to go ahead with this costly block and beam suggestion, you will find that there's no easy way around it, it's a person at either end and plenty of grunting, swearing and grazed knuckles.

HTH

[Donwill]

Actually I have a fairly substantial tree trunk 2ft dia at 18ins above grnd level in the middle of the area, the tree was cut down approx 15 months ago,the ground is clay and there is, possibly a lot of infill by the original builders. The local building control have taken an unholy intrest in the proposed foundations, there has been some foundation problems in the past with similar bungalows within 70metres,and in the estate, although , they were built in the locality of a pond. Consequently I employed a structural engineer to advise me.( well worth £70 I think). He advised against raft foundations and went for trench foundations to the satisfaction of the BI, with a suspended insulated beam & block type floor to reduce the risk of problems of ground heave. The "Fastfloor Heatsave" materials delivered(27sqM) are quoted as approx £1,000 which is expensive I guess, but I would be foolish to pay for advice by a professional and then not take it. My problem is handling the beams which are specified at 31 Kgs per metre hence the plea for advice from people who have actually installed a floor of this type. Thanks for your interest Regards Donwill

[Nick H]

I've install loads of these floors over the years and you do not nee to worry about breaking them. They are designed to be installed one wa only but they are still very strong sections and you would be har pressed to damage one while installing them however you choose to pic them up. They are heavy but two strong blokes can pick up a 4m bea (three blokes would make it easier) and you can then carrry/lift the into place. For what its worth, you asked a simple question about handling concret floor beams, how much more information was needed ? Go for it mate

-- Nick H

[The Natural Philosopher]

You will need two people with adequate fitness.

You can support them in the middle only, if you turn them upside down..

But I'd get a pair of slings and shoulder hoist them using those and walk them in.

You may need an angle grinder to trim them if they are oversize.

They are pretty strong - I doubt they would crack although 4.2m is a very long run..ISTR that I had to have a halfway foundation in at the center of a 6m span. That gave us 3m lengths to manhandle in - they were not too bad.

I suppose you could trolley them in on something if you have a smooth level run from where they are delivered, but in the end you are hong to have to lift each end and drop them in place somehow. As I said, rope slings at each end has to be the simplest.

A third person to get the spacing right with a block at each end is also useful..be wary of tapping them too hard with a hammer :-)Rubber mallet is best, or club hammer on softwood block.

[The Natural Philosopher]

I have to agree with you, it is fairly obvious to anyone who has.

[The Natural Philosopher]

Not at all. There are very valid reasons to do with soil movement on clay as well. If the ground is liable to shrink or heave - classic example being foundations that have cut through numerous tree roots, or a tree has been removed, or if indeed the topsoil is loose and unstable, then a solid floor will never be stable enough unless so much material is removed and subsituted with hardcore, that it ends up costing more.

Or indeed that the house is on a slope, and there is a large underfloor void to be filled anyway.

Wear gloves. Use strong people. Take it steady.

Oh and go for at least 70mm of styrene insulation. and watch out for cold bridges at the edges.

[PhilC]

Well said that man

PhilC

[Phil L]

Wooden joists and floorboards will have the same effect inthat the joists are sitting on the foundations just the same as the concrete beams would be...the biggest problem here is the tree trunk, or more to the point, the roots, especially considering it's in clay. This is how subsidence works, the roots dry out the clay, which cannot readilly soak water back in and so it shrinks causing subsidence in existing buildings, now that it has been removed, the clay /could/ swell and cause the ground heave the structural engineer mentioned, and this is what you have paid your £70 for, but a suspended floor is a suspended floor, regardless of it's construction materials.

Remember that whichever materials you use, you must provide ventilation under the floor.

[The Natural Philosopher]

Right. Block and beam it is. You have been well advised IMHO.

Absolutely. Same as me, and I have had no problems, and it went in fast and easy. Its just HARD WORK :-

Dunno what those are, i just used blocks, and beams made up for my job..standard poly insulation, a DPM and a screed..

So 122kg per 4m beam. Hmm ..That is pushing it a bit. It IS doable with two hard men..but its a bit more than I expected..its also a very long span. You will get some bounce on that floor.

If you can get four people, two poles and two slings and there are no doorways to go through it will be a lot easier.

The other possibility is hiring a small crane, or something like a digger that can do the lift and carry bit, although you will have to use slings to support at the ends, not in the middle.

If you have three tough mates who will help for a slap up meal with lots of beer, go that route. If its just you, I'd hire a crane or digger with a driver. With something with tracks, and a 2 meter reach you can crane them in.

A lot depends on exactly what you have there sitewise. If you can get right in over the area, and there is some hard ground, a crane of small dimensions will be the easy solution. 122kg is nothing or even a small digger at full stretch...takes about half a ton to make them tip over ..DAMHIKT ;-)

[Phil L]

The Natural Philosopher wrote: classic

This bit hadn't been mentioned when I sent my reply. :-p

[PhilC]

I believe the pincer type tool could be a Kerb Laying tool have used these for manouvering pressed slabs. Only seen beam and block on large scale buildings where the beams are craned in. Would it be possible to "crane" in beams with a mini digger?

PhilC

[legin]

Have you considered using floor joists, insulated and finished with floor boards?Could be stained and used as the finished floor? The use of the silent floor joists enables very long spans with minimul weight. Legin

[Steve Walker]

There was nothing wrong with your question Don, and I hope you find useful advice here.

[The Natural Philosopher]

So they say, but I can't see the point in ventilating concrete.

[Weatherlawyer]

For me, the term "concrete" might have helped. Or clairvoyance.

How long have you had that gift? Is it true what they say?

[The Medway Handyman]

I agree. What is it with some of the people on this group? The man simply asked for some help, not to be attacked. If I had any knowledge of the subject I would be pleased to help.

[Donwill]

Many thanks for the responses, will also look at " silent floor"

Cheers Donwill