In the end I decided to go for a open-plan kitchen. My architects first plans were open-plan however looking at the work involved was just too much at the time. I’ve come this far so might as well do it once and properly. I booked a structural engineer to calculate the RSJ’s so I could take down the internal walls and avoid keeping a supporting pillar in. 3 beams in total to obtain a layout as below. Cost of steel RSJ are going to be between £950-1150. Due to the amount of time this work will take I have no choice other than to re-locate the kitchen to the front of the property in the garage conversion until the work is finished.
Due to having some spare time on my hands while my contracting employment is very slow I continued the building works in March 2015. I had to send a revised structural drawing to building regs as they requested more info.
I worked on the right-hand side rsj foundations as the area was easy to access. My first job was to cut away the hardwood flooring and remove two long floor joists so I could start digging down. Referring to the structural drawing, the architect did not specify the concrete footing for one pier however I noticed it was calculated on the calculations. I decided to join the two piers up to make one solid one.
Before I starting knocking out any bricks I placed two acro props under the existing RSJ to be on the safe side. I used planks of timber under the acro’s to avoid them digging into the soil. The bricks came out fairly quickly. The mortar was soft after so many years underground.
I wanted the concrete one solid piece so I had to cut away some of the existing 450mm wide footing that was poured for the single brick wall a while back. This would also allow the bricks to sit more central on the concrete base rather than them sitting on one edge. It took over an hour to break it away by drilling many holes into the concrete using a big SDS drill and then cracking it away. I really needed to purchase a breaker for this task.
I went down below the existing new concrete footing and 2 bricks below what the house was sitting on. Keep in mind that the house is not sitting on on concrete, just bricks. I left in approx 100mm on concrete that was extremely strong, perhaps it was underpinned at some point when the house was built. I slightly under-pinned it from one side so the new concrete will interlock.
I placed shuttering to hold approx 550mm deep concrete, although it could have been just 450mm deep. I will be mixing the concrete with a helper. I found it was best to move a jumbo bag next to the mixer and open up a couple of bags of cement in a wheel barrow to speed up the mixing. Also like before I poured the water into the mixer first, 5 lots of blasts (sand and aggregate) followed by one lot of cement. This should produce a c25 mix.
For this side of the piers (two), the concrete based is to be as follows:
1000mm x 600mm x 450mm deep + 900mm x 600mm x 450mm deep =
(1 x 0.6 x .45) + (0.9 x 0.6 x 0.45) = (0.27 + 0.243) = 0.513 cubic metre.
Many assume that to mix this amount you require half a jumbo bag of ballast however to mix 1 cubic metre it takes approx 2.2 tonnes of material. That’s 2 jumbo bags and 10-12 bags of cement depending on the mix.
As I joined the two concrete bases into one and made the hole slightly deeper on one end I would require more as follows:
0.55 x 1.6 x 0.6 = 0.528 cubic metres.
That’s just half a jumbo bag in and another half to go. Good job I had a helper. By having a beam of timber and board on top it made tipping the concrete in really easy. I noticed the mix had too much water so I cut down on the amount of water I used for the next few mixes. Too much water weakens the mix.
The day after I removed the shuttering. I was surprised how strong the surface become after just one day. Perhaps this was due to me removing any surface water after an hour of pouring.
A few days later I knocked out some of the old bricks to allow me to key in the new engineering bricks. I had to re-adjust the brick as I noticed the house had a 50mm cavity below the render (approx 1m up from the ground level). I also double checked using my laser level the pier would allow the RSJ to sit central when the brickwork was completed to the top.
I placed some brick reinforcement mesh between the bed of mortar to strengthen the bond. I used a couple of different branded of engineering bricks that I had left over from the main build, they all have crushing strength of 70 N/mm or more.
I keyed the bricks as far into the wall as I could. A few layers more I was up to damp proof. At this point I decided to work on the 2nd pier. Quickly dig out the footing and get the concrete ready mixed this time due to the amount that is required. To make life easier I decided to concrete the extended-lounge floor and at the same time having the concrete poured for the other pier. Also purchasing more concrete will decrease the cost of concrete per cubic metre.
I started digging until I hit the old lead water pipe. This was still in use until i finally got around to connect the new blue pipe directly to the mains. I planned to move it out-of-the-way for the time being as the concrete will be going under the pipe. I noticed a small leak and a tree root that had made it’s was into the water source. I do remember when the drains were done on the other side of the wall this root was cut back.
It just goes to show how a root seeks water through brickwork and the damage it can cause over time. My neighbours trees are just too close to our boundary but that’s another story! I tried my best to bend the pipe back to close up a very tiny hole. I even thought switching off the mains supply and soldering the hole shut. It got even worse as it started leaking on the other side of the wall. I had no option to block off the pipe and connect the new blue pipe into the current water supply into the house.
Good job I laid a new PFPE water pipe from the street boundary right up the new kitchen when the extension was built. 6 hours of hard work up until 9pm in the dark. Sorry no images as I was just too busy digging, joining, feeding new Hep20 plastic pipe into the house.
Back to the footing….
This side involves a lot more digging as the earth was up to ground level already, 2 half days work actually. All the house bricks had to be removed so the concrete is one strong piece at 0.75 cubic metre. UPDATE:Actually poured between 0.9 to 1 cubic metre in to this with the left over concrete.
It’s very deep and 1000mm x 900mm wide, comes to shoulder height when standing inside. I also went deeper than the original foundation brick level, just slightly lower than the new wall foundation level that was passed by building regs, and into the wall to provide some under-pinning for even better strength. Some of the trench blocks had to be cut away to make room for the 1000m length concrete. I jet washed some of the new concrete footing to provide a good key for the new concrete that was going to the be poured. Job done ready for concrete. Moving to the floor..read up on how to pour an insulated concrete floor on the next stage like below:
As before the construction was the same, 150mm hardcore, 50mm sand, 125mm insulation, 100mm concrete slab followed by a 50mm screeding layer.
For the central heating I used shorts runs of 10mm Hep20 barrier pipe instead of 15mm that would be connected using a 4-way manifold under the timber floor. 22mm pipes will be taken to the manifold to reduce pressure on the heating. 2 small radiators towards the outside of the wall and perhaps one large one at the other end of the lounge. That leaves one spare outlet that will be capped off.
I booked in concrete to be delivered. I was quoted £318 for 2.5 cubic metre to be delivered after 9:30 am. Didn’t turn up on time so i called. At 10:30 I as told their truck had broken down and they couldn’t make it. I asked to keep me updated. Never heard from them again. The following week booked in with exactamix at £345 for friday afternoon as it was my day-off. Received a call they also couldn’t make it today, Monday would be possible. I had used them before at least they had the courtesy to keep me informed. I remembered seeing a concrete truck driving past one day. G&L concrete, called them booked in for the following day at £300. Third time lucky. Job done in 1 hour and they cleaned up perfectly.
The day after. Note the colour is more brown than usual. This is because the colour of the sand in the concrete mix was a red rather than the usual orange/brown sand. I can start brick-laying tommorow.
I cut an extra wide DPC to size and placed it on a thin bed of mortar. I trimmed the DPM and tucked approx 1 inch over the DPC.
I found it tricky keeping it level and plumb, especially when keying into the old brickwork and building a two-skin wall. The engineering brick had been soaked by the rain which made the mortar staining more than usual. It looks like a messy job however it will be drywalled and plastered over. I kept half a brick on the end to allow for the fitting of the doors architrave.
To assist keeping the brickwork level I clamped on a piece of timber as a guide. I got to almost to the level of the pad stones and measured the length for the RSJ. Using my laser measure I measured the length twice to be on the safe side. Any mistakes will be costly. Just the longest RSJ length is over £500!
I had some quotes last year for all the 3 RSJ including fabrication of the 2 joins. They were approx £1150. I was recommended G&D Steels in Birmingham by my structural engineer. The cost including painting the steels with red oxide paint was £940 including VAT. Almost £200 saved. I asked how they off-load the RSJ. They said kerb-side delivery, usually the builders helps. As It’s just me on my own I agreed for another guy to come along.
They usually drop the RSJ off the side of the truck onto pallets like this. This one is approx half a ton. The night before I got some metal tubing to use as rollers, trolley, planks of wood and a trolley jack ready just incase. I planned to roll the RSJ into the back yard.
The longest one took ages to move in. The trolley just wasn’t strong enough to lift one side up. We used the steel tubing to pivot the RSJ in the middle and then rolled it into the yard.
By placing planks of wood on the ground allowed easier rolling of the tubing.
Moving the smaller RSJ inside was fairly easy It took approx 30 minutes on my own.
This monster of a steel just would not move. Every time I managed to jack it up onto bricks it would topple over. I found I had to use concrete blocks instead of thermal block underneath to stop it tipping over. I purchased a chain block that lift a capacity of 1 tonne. The beam weight is 86Kg per metre. 5.7m = 490kg. Using trestles I managed to lift it to the correct height to roll it using planks and tubing like before.
I managed to get it closer to the inside. I used my laser measure to work out if the beam would be able to turn into place once inside. The distance required was over the RSJ 5.7m length. This made it more difficult as the beam had its connecting bolt holes on the left hand side to it had to be turned the other way before it went inside. Using a long steel bar I was able to slide it into position before rolling in. I will post a sketch so you understand it better later. Getting back to the work inside…
I measured the height of the main RSJ to work out how high the padstone will have to be placed so the brickwork above can be packed with mortar and slate. I used imperial engineering bricks to make up the last course to the height just before the padtone. Perfect! I just about lifted this padstone that must be over 40kg above my shoulders into place. It took 3 attempts. The first I dropped into onto the mortar too hard and it splattered out. The second attempt one side went to low. Finally the third perfect using the level. I checked the distance from the edge of this padstone to the other wall.
I ordered a 5.7m length.
5.737m from the edge of the padstone to the outer skin of the brickwork. I allowed a little gap to keep the steel from touching the outer wall.
The concrete for this pier was poured at the same time as the floor. To begin the brickwork i had to remove some of the old wall go get access.
Had to be carefull not to disturb the blockwork.
Part of the wall removed with a block placed on the concrete as a guide to check the brickwork will be built up plumb.
I marked the centre of the block and marked where the block will be cut. Allow for the 10mm mortar and wall starter on the blocks, therefore 15mm.
The concrete blockwork below the DPC was broken away using a hammer and bolster. 2 more bricks were removed so the new bricks could be keyed in.
I placed the bricks as a dry-run to check. The first row I made into a pyramid shape.
First row down with mortar. Not perfectly flat however it will be corrected on the next level.
I’m going to need lots more bricks.
Cut some more block work.
I cut the blockwork using a sabre saw and standard wood blade. So easy! Don’t forget the DPC. I used some wide one.
I fixed the wall starter on both blockwork and old brickwork. I used some reinforcement mesh too to make it stronger.
The brickwork looks so much better when you have space to work and somewhere to stand!
Almost to the ceiling height.
I had to remove more of the old brickwork to make room. Also the floor joists for the bedroom above will have to be cut back.
I marked the levels onto a stick so I could match this side to the other one. Using my self-levelling laser I marked the blockwork exactly where the padstone should sit. The next few courses I will adjust to get the level perfect.
Once the engineering brickwork was complete I attached my laser to the roof joists and aligned it. You can see it is approx 50mm below the concrete blocks on this side.
I placed some blocks so I could easily lift and place the padstone into position. This part got very stressful. I had to slide the padstone while lifting the padtsone into position in such tight space. Like before it took 3 attempts to get it level.
Absolutely perfect. I could say that I work to 2mm tolerances! although this depends how accurate the laser is. I will find out later when the beam is in. Ready for steel now.
Firstly attempting to lift a RSJ that is 500Kg using my method is extremely dangerous. Any accidents may result in death. Builders will use two genie lifts for this step. I searched way to lift an RSJ on the internet and found this shocking image see here. The image says it all!
I calculated and tested my method on the ground before lifting to this height.
I calculated the weight of the steel. 5.7m x 87Kg = 490Kg.
One chain block has a lift capacity of 1000kg. To be on the safe side i planned to use two chain blocks on each side that would lift just 245Kg on each side. The main advantage is the beam will not swing and the load on the roof joists will be halved. An average man weighs about 80Kg, so thinking would 3 men be able to stand on a 175mm x 50mm joist one metre length?? I guess so.
I took a piece of the same timber beam across my scaffolding tower sideways. Placing timber sideways will allow it to bend and the strength is usually when it is upright. I lifted the steel beam up from the ground 1 foot using only one chain block. Lifting 490kg it did bend slightly however it was still safe. If the loads were halved and the timber was placed upright It will be more than efficient lifting the load. To be on the safe side I only lifted the steel one foot a time and supported the steel underneath just in case the chain block failed.
I had to purchase 4 one tonne slings to wrap around the roof joists and the steel. Since the roof timbers are already loaded with the weight of the tiles I planned to add acro props to support the roof joist that were supporting the chain blocks.. While lifting I found the roof did not move one bit, as the acros nuts did not feel any tighter when turned.
The beam soon got to head height and I placed the next level of scaffolding underneath. I supported the beam on the tower to reposition the chain block so the beam will be able to swing onto the Padstone.
More images comming soon….
For the 2nd Beam please read 2nd RSJ