Thursday, 14 April 2011

Early Blockwork

We had the block and beam in place with a concrete screed, the drains were in and so the next stage was to start the internal block work followed by the outer skin of brick. 
Having been to the Homebuilding and Renovation show at the NEC and come across the 'Thin Joint Method' of block work and being suitably impressed by its ease of use we decided to employ this method in our build. One of the main advantages being that I could lay blocks well ahead of the brickies as the ties are inserted into the block rather than in the mortar course. A SDS drill,(a cheap model £45 from Axminster Tools) is used with a special tool to drive in the stainless ties at every sixth brick course as one builds the outer course.
This system is a little unforgiving of sloppy workmanship as it is essential that the first course of blocks has to be layed on mortar and has to be dead plumb and level across the block. The thin bed joint is only 3mm thick and there is very little room for adjustment as the wall rises.So that was the first job, a single course all around the build including internal walls as these were block work too.

The first of the Celcon Aircrete Blocks arrives on site

Celcon and no doubt Thermalite supply all the tools necessary to do 'Thin Joint Blockwork' and they consist of a scoop (for laying on the mortar) a coarse sanding block for adjusting the odd block and a very coarse rasp for removing large amounts of block if you do go wrong. Block hand saws are readily available from builders merchants(they don't last long, we used four on this build) and the one part mortar is also readily available. The mortar is mixed in a bucket with a whisk. It is only necessary to mix small amounts (1/2 a bucketful will lay about 15 blocks) as the mixture goes off pretty quick and once layed is bonded to the blocks in less than 1/2 hour. As in all block work joint bed reinforcement should be used every third course and especially around openings, but the manufacturers literature gives guidance on all these issues. We purchased our stainless ties and expanded joint bed reinforcement from Tackburn Ltd.

First couple of courses of block work in place

The technique is fairly straightforward as you can see here where I am using the scoop to butter the end of a block. The bed has been prepared with a layer of mortar next to the door. The system is very quick and requires no great skill, just follow traditional procedures for raising a wall, corners first,then builders line between to give a straight and level line.One drawback to this system applies when lintols or other non aircrete block elements are to be incorporated into a wall. In this case resorting to conventional mortar is required for bedding and making up as these elements do not meet the very close tolerances of the blocks.

Sawing Blocks is simple, but the square(orange) also supplied by Celcon was not very accurate.

Preparing frames for openings.

The block work rises to first floor level without any bricks being laid.

These were extra wide aircrete blocks used down the centre of the build where a structural  wall was required.

A good cup of tea and a biscuit helps the job along

The block work was nearly up to first floor level and by this time I had chosen to lay the first courses of brickwork up to DPC level.  Then one ill fated day after long deliberation I decided that I would carry on and lay all the bricks for the house!!!! It was a difficult decision, I knew I could lay bricks but not at the pace of a good brickie, actually at most 150 a day, but both my wife and I are control freaks and perfectionists so it was inevitable really!

Next time in my blog I will show you how we did some of the brickwork, especially around the windows and the garage doors.

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Sunday, 3 April 2011

Getting on with it

On site at last, living in the caravan, services laid on we could be working within the hour and make some progress. 
We had it in mind to find a bricklayer and had been asking around for recommendations, now we would need one in a couple of weeks. Acting on suggestion we visited several other building projects in progress and completed but to no avail, we were looking for someone who apparently did not exist,someone who could lay bricks that were neat, clean and well pointed. It was quite disappointing the quality that we found.  On the other hand a local builder in the village whose quality was exceptional gave us a quote which amounted to almost a pound a brick laid, but this was too rich for our budget.

Finding the right bricks was another problem as we were looking for something with a rustic feel. I had used Marshall's Old Mill bricks in the past which was close to our desires but a little too colourful. Then travelling through a local village one fine day we came across a development of new flats with bricks we loved (loved??) and speaking to the brickies we had potentially found our bricklaying team. The bricks were Hanson Cheshunt Multi, a good quality rustic looking brick with fine colouration and very appropriate for our village. All I needed to do was finish the foundations !!
First of many deliveries from B&Q Trade

We had laid the first course of block work around the site to delineate the walls of the house, checking the diagonals for square (+- 15mm)We then raised the inner course to under floor level ready for block and beam. Two courses of blue brick (overkill) were laid on top to bring the finished floor level up to the desired height. We were now ready for the floor.

Finishing the foundations

Hanson's had designed the floor for us from the plans and they arranged delivery to site within a few days of requesting it. We were now installing a block and beam floor ourselves, something we had never done before! 

B&B delivery


Relatively simple job really, just need a crane (or lots of labour) to move the beams. A good quality dry laid DPC (Hyload Housebuilder DPC), beams lifted into place and spaced according to the diagrams supplied by Hanson and spacer and infill blocks mortared into place along the top of the wall. Not to difficult?
A final course of bricks around the periphery to act as shuttering and infill with insulation and we would be ready for screed. 

Help to move the Beams
Local Crane Hire

First Beam

Crane drivers mate helps with the Beams

Spacer Blocks waiting for Installation

Solid Blocks for Garage Floor
All beams in place,now for the insulation. Brilliant design, easy to install, just slips into place, a couple of days work and its done.

Ready for Insulation

Simple to Install

Nearly Done

Well Earned Break

Garage Floor needed Mesh Reinforcement

Not so easy the next stage, laying the concrete screed. This had to be a bit more organised, labour in the form of friends and relatives, a vibrating concreting beam, a concrete pump to get the concrete to the back of the site and several loads of specialised Lafarge Fibrin concrete. All went well until the concrete pump arrived, brand new six wheel vehicle with an equally new driver who immediately said he could not do the job because of the danger of the overhead power wires. Calamity, we now had to man handle the concrete to the back of the site walking along the beams trying not to tread on the polystyrene insulation. We started and what should have been a relatively straight forward job became more difficult. The vibrating beam was f****** crap, worn out and held together with loose nuts and washers it eventually shook itself to pieces, and this was from a reputable hire company. Despite the panic we did get the job done eventually but it was down to the efforts of my family and friends that we succeeded.

Vibrating Beam(do not use one of these)

Despite all we did mange it
Well that was it, up to ground floor level, floor laid, drains in situ, just a small question of building the rest!!

In my next post I will describe how we started the block work which we had planned to do and how the brickwork became our job also which we had not planned to do. 

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Finally we get to live on site

We had completed much of the preparation for moving to site, installed the caravan, built a storage and site hut, connected temporary mains and had BT connect us to the telephone in the caravan but we still needed water and drainage. We had to construct the footings before we could lay the drainage so we could find the correct line and they were not in the way. But here's the rub, we had applied to the sewerage authority for permission to connect to the main sewerage and also a connection to the surface water main (unusually), but a shock came when they informed us that we must stop work immediately. Apparently because our building line was close to the carriageway and there was an old brick culvert for surface water in the verge, and they  did not know the line of, we would be required to have commissioned an optic fibre survey of the culvert in order to establish its position so that we did not compromise it with our building. We could not therefore carry on with the footings until the survey was complete.  aghh!! Foiled again!!!
So we reluctantly downed tools and abandoned the site to await a survey.

Meanwhile the electricity company had also noted from our plans that because we were building close to the road and as the building reached roof height it would be perilously close to the open wire mains supply to the village and preventative measures needed to be taken. Oh! OK what does that involve?we asked.

You can see the offending open wires in this picture
Well what it involves is 'Money'. We had to pay for the open wires to be replaced by what they call ABC cables, three cores twisted into one cable. Fortunately as the poles carrying the wires were old and needed upgrading we only had to pay towards the work but the bill was still over £1200.00. And to our embarrassment the village power supply had to be off for the best part of a day.

It was about a month after we had stopped work on the foundations  that the optic survey was scheduled to be undertaken and the survey team duly arrived on site on a cold, wet, snowy February day.

That's me waiting for the survey engineers to arrive.

It was a bit of a waste of time as in the event they tried to access the culvert from one end which  was completely silted up and from the other it was partially collapsed preventing  the 'optic mole' entering the culvert.  It would take months to repair the culvert and we could not wait. It was a bit of a stalemate. In the end after protracted discussion and because of the Water Authority  not  wanting not to spend the money that they relented and allowed us to carry on but with great care. It turned out in the end that when we finally connected to the surface water sewer we found it only a few inches under the kerb outside our property and our foundations would not affect it at all. Panic over!

Right we 're cooking with gas and our friendly JCB driver from Squires of Southwell arrives to excavate the footings. A couple of days and they are dug and ready for conc. Squires lorries take all the spoils away for us.

JCB at work
Just checking

Me and my trusty laser level. A very useful buy
What you doing down there
Ready for concrete

There are many suppliers of concrete in our neighbourhood as I am sure there are in yours but just down the road there is a quarry belonging to LaFarge and we therefore had cause to speak to their rep. We knew we would require special concrete for screeding the 'Jetfloor' block and beam which contains reinforcing fibres, but as there was limited access to the back of our site and we were short of labour to manhandle the conc, he suggested we use one of their products called 'Agilia Trenchflow' and boy am I glad he did. This stuff is like water and flows much the same, so much so it will find its own level even after flowing several metres. It only needs a little help around the bends occasionally. Great stuff!! Only drawback, yes you've guessed it,expensive.

Forty Cube to go
Flows like water
Checking again

Finished Product
The first of many blocks to be layed.
Contractors connect us to the mains

My wife had a go
Drains nearly there

We used standard dense concrete blocks to get us out of the ground with cavity construction. Weep holes were provided on the outside and concrete infill with 45' slope between the leaves. Once we had a line on the footings we could get the drains in and connect the caravan to the mains. Our mains contractor generously supplied us with Osma drainage products at trade prices but as these were prohibitively expensive at normal prices we reverted to Marley products from B&Q at much less cost for the last remaining sections.

 At last we were connected to the mains, we had water and we could go to the loo!! Now all we had to do was to move all our belongings out of store and move into the caravan which we duly did. It was a relief from the daily grind of travelling thirty miles to start work and returning in the evening seven days a week. We could now roll out of bed in the morning and get on with it.

My next post will deal with how we finished off the block work and installed the block and beam floor.

If you have any questions about my blog or self build in general please email me. You can find my email address in my profile (top right of page). You can also become a follower of my blog by pressing the follower button or click on 'Comments' below to leave a message.  

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