Monday, 16 May 2011

Up to the roof

We were well on with the brickwork now, mostly up to first floor level, double lintels over all brickwork openings where there was a curved header, conventional cavity lintels elsewhere, block work also up to first floor level, it was time to start thinking about installing the block and beam on the first floor. We had plumped for b&b on the first floor for reasons I outlined in a previous post and Hanson Building Products had designed this floor for us, however it involved some steel work 
There were several pieces of steel, all of which had to be supported on pads of three courses of engineering bricks. The steel was designed-in, in order to keep the concrete beams short. The alternative was beams in the order of 7metres long which would have had a considerable upward curve in them causing problems later. The beams in most instances sit on the lip of the steel rather than on the top, this lip is at maximum 75mm wide. It was quite disconcerting to think that there was all that weight, blocks and beams sitting on that narrow a piece of steel, but as Hanson's said it was fine, who am I to question it. Anyway they have been sitting there for the best part of five years now without any problems! 

The family gets involved with the installation of the steels over the ceiling. The nearer one is a conventional I joist which supports the outer skin of the wall and the other is a C joist which      supports the floor beams and the inner skin.

Steel joists which span the living room. The beams rest on three courses of engineering bricks at either end and consist of two C section joists back to back. The beams sit in the C.

I was also a bit concerned about concrete beams sitting directly on top of an aircrete block wall so I layed a course of bricks along the top to act as a pad for them. I love extra work!!

Crane hire to help move beams
Beams swing into place

Once the beams were in it was a simple slog to install all the blocks to make the first floor. A dry mix of sharp sand and cement was then brushed into the voids to firm them up.

As my wife is the resident photographer she would often not get in the picture, so here she is moving every one of the floor blocks onto the Bumpa.

 And here's me taking them off  at the top to fit them.

The Bumpa was a very useful tool and kindly loaned by a local builder.

Not everybody would choose to use block and beam for the first floor of a house but being old in the tooth and preferring a solid feel to its construction we decided to do so, however it is not without its drawbacks. The most significant of these is that there is no cavity between floors in which to run cables and pipes and together with using solid walls up and down location of services presented some issues. It is normal to lay a screed on the blocks but without constructing channels in the screed again there would be no place to put the services. In the event we were to construct a mesh of 50mm square timber both under and on top of the floor, one to support plasterboard and which would provide a cavity for cables and another on top also incorporating a cavity for pipework and to which we fixed the  flooring.(more pictures of this later) Perhaps not the most elegant of solutions and one that most builders would avoid but it has given us a solid floor and no creaking. 

It was at this point that another decision was made which was to lead to a rather large hole in our pockets but hopefully increased the value of the house substantially.

The original planning permission was for a four bedroom house over two floors but we thought why not make use of the loft space and increase it to five bedrooms and an extra bathroom. Wow! just like that. Actually it wasn't too difficult,  by extending the b&b floor area over the hallway, incorporating a second set of stairs, roof lights and loft trusses it seemed to be achievable, so we duly submitted our proposal to the authority and to our surprise they agreed with the proviso that all occupied rooms had fire doors to the stairs. It was also necessary to include fireproof plasterboard to the underside of the floor, and so that's what we did!!  

Block Work first floor(must be the tidiest site ever)
Almost up to wall plate
The floor was in and we now carried on with the block work up the the bearing plate for the roof trusses, this was easy as it could be done from the inside standing on the b&b floor, however to complete the brick work up to the same level it was time for scaffolding. 
Well we like so many self builders were in a quandary about scaffolding. What was the best solution, buy the normal stuff and sell it later,(horrendous cost) hire it and complete the build in a limited time frame,(not for us as we could not meet the timescales)or buy it from the guy from Grimsby (I forget the name)who buys it back from you at a reduced cost. Then along comes our local friendly scaffolder who offers to hire it to us for a fixed charge and unlimited timescales, (I think he took pity on us) and we were off again, lucky devils?    

 Scaffolding in place and we can carry on up to the wall plate with the brick work. Note the scaffold hoist, bought for £800 and sold on eBay for £500, probably the most useful tool we bought throughout the whole build and absolutely invaluable.

The brick work is now up to roof level and before we can continue to the top of the gable ends and the chimney the roof timbers need to go on.

In my next post I will show you how we put the roof on and describe some of the construction involved. 

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Thursday, 5 May 2011

Brickwork here we come

We have just spent the Easter break decorating a flat (we should get a life) so I am a bit late posting the next episode about our self build which narrates how we tackled  the brickwork and some of the details involved, but here goes. 

I had done a lot of brickwork beforehand but nothing on this scale (about 15,000 bricks) and it was a daunting task, but not being able to find a good brickie at the right price I had to have a go, after all how difficult can it be? Well in the end, not too bad really, long and slow but very rewarding and definitely something to be proud of. In keeping with the theme of traditional appearance we designed the house with a base of blue bricks which appear above ground level, originally these would have been as a DPC but now days regulations insist on a proper membrane as DPC. We had included them for appearance sake. Laying blues demands some experience as they tend to float on the mortar but its a case of laying them quickly and accurately and then leave them alone, the more input the less success. Anyway I had managed to lay the blues up to DPC and I made a start on the facing bricks. The first task was the fireplace as this formed part of the internal walls. I included lime in the mortar mix for flexibility and also for appearance as it gives a creamy colour to the finished product, however if the brickwork is not clean it does show up rather badly on the facings, you live and learn!! 

The fireplace forms part of the inner skin, the blues will show above finished ground level.

I then started raising the corners for about eight courses in the traditional way, (I know there are more efficient methods but that involves spending more valuable cash)
Admiring the first few?
Raising the corners

Raising a corner. Not pointed up yet I hasten to add.

My wife gets in on the act by planting piles of bricks all round the site. Just to keep me going you understand!

Of course as one raises the outer walls insulation must be included and in our case we had decided to use poly.. polyis.. polyisocy..polyisocyanurate, (PIR for short,thank god) partially for idealistic reasons but also it can stand up to wet weather, I never could understand how rockwool and the likes continued to insulate once it got wet.

Adding the insulation, the bottom course sits on the butterfly ties which were included between leaves below ground.
Demonstrating installing helical ties.(there was no insulation necessary at this point) Pictured at a much later stage you understand.
One of the features that we wished to include in our build was stone sills, well in our case reproduction concrete sills(a pretty good compromise)which we had made locally at our independent builders merchant(John Stephens of Nottingham). There is a technique to installing sills in that they should be wrapped in DPC on the underside and bedded on mortar at either end. The cavity is pointed up after all the remaining brickwork is completed. The idea is to stop the stresses and strains of the drying out process cracking the sills, simple! 

Cutting DPC ready for another sill

Sill in place but not yet pointed
 Once the corners are up and using a taut builders line brickwork can be infilled between. Normal rules apply, keeping perps in line, checking for verticals, maintaining a clean cavity and pointing up regularly. The method I used for pointing up was to apply a bucket handle, what!!! yes that's right a bucket handle(a steel one shaped to form a tool and which I happened to find in the loft of my original home many years ago) to the mortar joint, then brush with a stiff household hand brush to remove excess mortar finally giving a  finish with a soft household hand brush. Pointing tools are readily available from Merchants and DIY stores.

Brickwork well on the way

Other features which we wished to include in our build was that where ever possible to incorporate curved headers to the window openings and to install the windows behind the brickwork rather than in between which is the modern practice. These features both present complications so are generally not used in mass building schemes. The former involves making formers to support the bricks whilst they dry and also prevents the use of a conventional lintel as the internal and external leaves need support at different levels.The second feature involves the opening in the inner leaf being wider than the outer leaf to accommodate the window frame. 

Curved headers wherever possible

A completed window. The frame is behind the brickwork, a traditional feature found on many old buildings and designed to offer some protection to the window itself.
The garage doors were to be treated in a similar manner so that the reveal for the doors was on show, there would be curved headers and the character and appeal of the building would be enhanced. 

Curved formers were made to support the brickwork whilst drying. This technique involved a long piece of string, a stake in the ground and drawing an arc on a pieces of particle board. Some guesswork going on here!

Trestles and boards were used up to first floor level, beware health and safety.

Conventional Lintel to take the weight
From this much later picture you can see how the garage doors are set behind the brickwork which adds greatly to the character of the building.
Well that's about it for this post, the brickwork is up to first floor level and we will soon be ready for the next stage.

In my next post I will describe the installation of the first floor, much of the remaining masonry and getting ready for the roof.  

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