No problem-I did all the walls myself.FBT laid the first layer of blocks acurately level (with the aid of a laser) and I went on.I never laid a brick before but it was easy enough. 2 weeks for the outer walls, 4 weeks for the inner walls,lintels,ring beam.That was the spring/summer 2002,if you remember it was bad weather so I wasn't out every day,had to order steel and cement, sand,shuttering timber etc..So with better planning it would have taken only 4 weeks incl.the ring beam for a single story house.
FBT can recommend a small crew to do the job for you,they also offer training for the DIYer.
Forgotten:No,I did not use any extra insulation.Just the poroton blocks ,365 mm "SX 13" at the time ( u-value is less than 0.3).But there are now even better ones,"%%WORD22%".Since the wall is an important part in the building go for the best you can get.An extra few centimeters cost very little extra,the labour is the same as is the plaster or paint.
Thanks for that. Sorry a bit brief last time - baby wriggling in arms, and hear her muttering now again so no time now either Anyway, we are very interested in this - it's for a big extension, and lots of timber frame companies won't touch that, so looking at alternatives. I was under the impression, misread the blurb, that you ended up with a wall with u-value of .12, which I thought was great, turns out it's .26 which isn't quite as mind-blowing as I had thought, but still worth considering. dh is fairly handy so he might have a go himself - crap, screaming child - going to call one of the "previous projects" in the area and see if we can have a chat. What's %% WORD %% btw? Thanks again.
"%%word etc." was somehow misprinted.It should have read %%WORD7% (Es Ix eleven)which is the last generation of poroton blocks.
The thermal conductivity of these is 0.11W/mK.So even better than the %%WORD25%(Es Ix thirteen) blocks used by me.I suppose the name/number of the different blocks represent their thermal conductivity,"thermal conductivity" is not the same as
"U-value",maybe that is the reason for the misunderstanding.
If you or your dh can throw the darts or fire a gun than you can look straight.That enables you to put up a wall straight.Some people have difficulties to determine an angle of 90 degrees.But there is always the spirit level and the rope to make sure.
PS :Large letters in combination with numbers do not come out on AAM texts,hence the %%WORD%%.
I'm going to be a devils advocate (because I would love to be able to go down the poroton DIY option).
Isn't there a high risk of "messing it up" when you look after the block laying yourself? Are there some sort of safe guard like getting an engineer (or someone like that) to check your work every few weeks.
My fear is that in saving 5k or 10k or 20k I will pay for it in 2 years or 5 years or 10 years because of my own shoddy work. Or am I:
a) giving a bit too mush respect to the noble art of block laying.
b) unaware of how simple the poroton blocks are to actually lay.
Once you have the correct drawings-and you are able to read them- there is no problem with going the DIY route.
If the foundation has no problems the walls won't either collapse,provided you put them up straight.There are videos available from the various poroton sellers around Europe (FBT in Ireland)that will show you how simple the job is.
And of course it is better with every building project to have an engineer looking at the various stages.He will also sign for the bank(mortgage) and the insurance.
There is the noble art of masonry and there is the dumb job of brick laying.Masons can build cathedrals,bricklayers couldn't.But poroton is a bricklayers job,you do not even have to be literate to understand the techniques.Once the wall stands it stands for "ever".You don't have to worry about shoddy workmanship,especially when you know every single brick,every corner,every lintel since you did it yourself (under supervision of an engineer if necessary).You couldn't say that about any house bought ready to move in.Once a wall is plastered no one knows what lies behind,did they put in insulation,are the pipes leaking,are the bricks good enough,is the dpc o.k....?
Do it your self and you know what you have.
How does cost of poroton compare to standard cavity construction, assuming you do the work yourself? Single leaf construction, so I assume half the number of blocks. No bricklayer to pay. So what about the blocks themselves?
To get an estimate you better contact FBT directly or check the web under "Poroton" and import the bricks/blocks yourself.Poroton blocks come in various standards(U-values) and also sizes.Poroton is not a brand but a patented brick , so there are many manufacturers -and prices I guess.
I used FBT because they are in the business and know what they are doing.Just send them a copy of your drawings/sketches which include dimensions in either feet or centimeters and they help you further.Do the same with an "ordinary" bricklayer or builder and than compare yourself-shop around.
"Trost" in Hessia/Germany where the manufacturers of the bricks I used and I think they give prices of bricks in English on their web page .Try "Poroton plus Trost" or something like it.
Costs can vary -much depends on the number of lintels,corners etc..
I think I paid a total of 6.000 IRP for the material delivered to the site.
Already in touch with FBT and awaiting quote, They seem like good people based on initial phone contact. Are arranging site visits for me, as well as self-build references.
Any thoughts on integrating a Poroton extension into an existing rough stone two-storey farmhouse? My main concerns are:
1. How to properly bond new construction into existing. Is it done in the normal way, i.e. by removing stone from existing bldg and jutting the new blocks in on every second course? Could be difficult to do that, given the uneven sizes of stones in original building...
2. How to maintain continuous damp proof course through new construction/existing walls (with electrostatic dpc)/new concrete floors in old building...
The area I am building in (Donegal) has few if any available builders due to bungalow bliss proliferation coupled with celtic t*g*r, so self-build is inevitable.
To integrate the new wall and to make it bond you should use wall anchors- some call them mason anchors.You should make sure that the plaster is sound on the old wall,otherwise chip it off down to the stone.The anchors are something like a big plug and screw and are hight adjustable , so there is no need to take out the stones from the old wall.(In fact it would be better not to disturb the statics of an old settled wall.)These anchors come either with a strip of non-corroding metal or with a similar bar of metal.This will be fitted in the place between the poroton blocks-the grout.Since there is not much space between the blocks(thin bed mortar) you use a rough metal file or a medium grit timber file and create a small space in the block where the anchor goes in .This is the standard method and used as well with partition walls where they join the outer wall.This should give your construction the necessary strength to withstand a smaller earthquake without cracks in the wall.
The dpc in the new part should be no problem,standard building methods will aply.If you have the time and money you should go for aeroboard insulation UNDER the slab,check the Aeroboard web page,it seems to be logical what they suggest.On the continent it is standard method-in most countries it is part of the building regulations.With this insulation you can integrate the waterproof course as well as the radon barrier.Once you are at it try to include a duct for water,sewage,electricity.Shorter ways cost less,and a central supply is usually the shortest and you have no pipework running(-and to be maintained) on the outside of the house.
Now,for joining the two dpcs I don't know.What is an
"electrostatic dpc"?Is it the dpc that uses a permanent small current which alter somehow the behavior of the water?I haven't dealt with them,so no own experience.
But I would say if you overlap the new dpc for about the width of the old wall plus a bit extra - 5cm or better 10 cm- than you should be on the safe side.But ask the Fbt people or an engineer or check the web pages of the manufacturers of the electrostatic dpc to make sure.But why should the el.dpc not work with a layer of plastic on it-I don't know.
Once you have the digger for the foundation on site you should consider to lay a drainage pipe all around the building,that will improve most damp sites enormously.
The yellow drainage pipe doesn't cost much and some grit to backfill the trench neither.Additional piping for water,sewers etc. can be included in the trench.On most sites the digger stands around idle for some hours during the agreed work time so that shouldn't be a problem as long as there is access to the house .And the quarry where you get the hard core for the foundation usually gives a better deal on the second load once the driver knows the way.
The trench around the building is something I'm very interested in doing as the site is indeed pretty damp judging by the state of the existing building. How close to the foundations would you recommend the trench should be. I don't want to destabilise the ground around the existing building.
I can't compare the noise insulation effect between the poroton blocks and the trad.cavity walls.I used to live in a traditionally cavity wall building with the usual day to day noise from the road and neighbours but in my new place (96m2) I live in a rather rural area.If you check the web page of poroton they give you all the details.There are different blocks in different sizes available so you have the choice.From my personal view it is about the same.I think the windows/frames are a major factor rather than the two different walls.
Sorry, started this thread and then abandoned it. Thanks a million heinbloed for all your information since. With a two-year old and a baby, I don't get online that often.
After much dithering and debate looks like we're going to go with the poroton after all - abandoned briefly in favour of timber frame but back to it now. Looks like dh is going to go for it himself but stupidly, as he's a teacher, we've pretty much wasted the summer, he could have had a good chunk done during July but time running out now. May have to rally the troops and do a barn-raising on it. Like extopia we're doing an extension - 1000 sq ft on old mass-concrete 1.5 storey cottage in Meath. Extopia, have you started yet? How's it going? There's a new Lidl being built near us here in Trim and it seems to be flying up. Maybe we should start a poroton-selfbuild support group!!
Yes, I've started. A few problems, but generally going all right. Most of my problems are due to poor site access as it proved impossible for FBT to get their truck into my site. Had to unload up the road and get the blocks into my site with a JCB - expensive, but would have had the same problem with ordinary blocks.
The poroton blocks are very brittle and chip easily. There were quite a few broken blocks in my first delivery batch due to the difficult transportation but FBT says it will replace these if it turns out I don't have enough. A further delivery was carried out by a third party courier and again quite a few broken items.
The blocklaying itself is easy enough, but heavy going. You would need a helper or progress could be very slow. I have never laid a block before and we're up to ground floor lintel level after 2 days. Although FBT claim you can't go wrong once they've laid the first course this is not really true. It can be tricky to get your walls plumb vertically due to the non-flat outer surface of the blocks, making them less than simple to line up visually. A straight edge, line and a level are important to check this. My first course was laid just before dark and the FBT people had to leave right away so training was minimal to say the least. Would be good to make sure this does not happen to you and insist on them staying (I wish I had!) You need to have your wits about you and not to panic if something goes wrong!
That said I am very confident I can complete this project myself (two 2-storey extensions, totalling about 750 sq. ft.). Will post back as the project progresses.
Sorry for your trouble with the broken blocks,I had the same.But it worked out fine,poroton did actually put a few more in the load to make up for them.When the walls were finished I had 5 blocks left over.With the aid of the mortar LM 21 -probably included in your delivery- you can repair a block ,the LM 21 has about the same U-value as the block.
Which blocks did you use,which size?
[SUEELLEN, HOW ABOUT RENAMING THIS THREAD "POROTON BLOCKS", MIGHT BE A BETTER GUIDE TO OTHER USERS]
I have not been posting much lately due to blocklaying duties!
Using SX12 block, external only, 365x250x250mm.
Yes, can use chipped blocks, repairing with the LM21, but would not chance ones that have lost more than a bit of the outer edge.
At this point have installed the ring beam on the second storey and am now in the welcome position of actually waiting for someone else to do work before I can finish the job (need the roofer to set the guide rafters so we can do the gables).
All told, the project is going well. I built the two 2-storey extensions to ring beam in about 18 working days (with help, you need someone to get the blocks up to you, to mix the glue, and to generally keep you sane when thing go awry). There were some problems along the way, which slowed things down: we went off level, meaning much shimming up of blocks in certain parts of the wall. Don't know how this happened but it did... Certainly very hard to stay level once you cut a block vertically (as you may have to do over lintels) or once you move off the thin-joint mortar to the LM21 in a single course (again over lintels, for example). But the trick is, don't panic, remind the blocks that YOU are in charge (hey, you do a lot of talking to yourself when you're self building, and I mean literally self building!).
There is a huge amount of satisfaction attached to doing it yourself. This can be tempered by the sceptical comments of other subcontractors as they arrive on site and inspect your work. Nobody, apparently, has "ever seen the likes of them blocks before." Happily, the sceptics are starting to admire the blocks now, having seen the method. And if you are building in a part of the country where it's difficult to find subbies and labourers (despite so-called local economic hardship), you get a bit of kudos from disbelieving building pros for doing it yourself and moving the overall project along.
But we're not out of the woods yet. Still got to do those gables. Glad you had blocks left over heinbloed - me, I'm about 150 blocks short right now, due perhaps to the large number of broken blocks in my original deliveries. (150 blocks is a lot, nearly 10 sq metres worth). Luckily another local FBT client has about 150 blocks left over, so I'll be able to do a deal with him. Coincidence?
Generally, FBT have been fantastic people to deal with with regards to taking time to answer my sometimes very naive questions. However this is to be expected as they actively encourage people to do it themselves. Wolfgang (the German with the Wexford accent) is always available to help with queries.
My considered opinion? Doing your own blocklaying is not for the faint-hearted. Very hard and heavy work. You need a helper. If you have to pay the helper the cost savings are obviously reduced, especially if things go slowly. Then again, try getting a blocklayer to quote you on poroton blocks! Not easy. Would I do it again? I doubt it.
heinbloed, did you buy the external waterproof render from FBT or from elsewhere? Obviously the render is critical for a single leaf construction method to work, so I'd like to know your experiences both with your plasterer and aslo with living in the building afterwards. The blocks are very porous and seem to suck in water so the external plaster is vitally important. How'd it go for you?
And what about such mundane things as putting in vents and making outlets for waste pipes etc. How did you achieve same?
We are following your progress with great interest for our extension hopefully next year. Like Aisling, we have a mass-concrete cottage and a very small baby!
Dh is quite good at all that outdoor stuff, but cost is a factor. Has anyone done the overall sums for the cost of a 1000 sq ft extension??