On The Tiles

With the rafters in place I covered them with OSB3 to stabilise and give added protection and strength to the structure.  The roof membrane was stapled on and battens nailed into place to give a 3.5" tile overlap.  I decided to use second-hand tiles; not because they are cheaper, because they aren't, but because they would fit in to the picture better.  I bought them from a guy in Dereham who had demolished a barn and had sufficient.  They're heavy things, tiles.  It took 2 trips with car and trailer to collect them.  As it happened he also had ridge tiles which are more expensive.

I bought 4 velux windows which came with the flashing and seals.  For these I had to cut out the spaces I had left in the rafters and fit the frames.  I hope I have used sufficient extra felt and sealant to ensure they are all watertight - but it wall remains to be seen.  I assume we will get plenty of rain between now and when I insulate and finish the ceiling, so I'm sure I will find out.

I have decided to go with 'wet soffits' - where the ends of the final line of tiles at the gable end are mounted on mortar which requires a fibre board underlayer. It means being much more accurate with the cut tiles and the spacing up to the first velux window.  There will be a fair amount of trimming needed to fit the tiles around the windows, but I'm sure it will all be worth it in the end.

The gulley is the next thing requiring finishing.  I have laid the board on supporting timbers to give a 2" fall over the length and painted it all with Flexacryl fibre-reinforced paint.  Martins Plastics told me that this stuff is good enough to line a gulley without fibreglass, lead or plastic and will stay waterproof and flexible forever.  However I am going to lay a fibreglass gulley once there is sufficient heat in the air - I need a good 10 degrees to enable it to cure and it has been frosty recently so I need to wait a while.


Meantime I built a hopper to take the water discharged by the valley and drain it to a downpipe.  It is a downspout from the old guttering, cut to length and encased in an OSB frame which is wrapped in fibreglass inside and out to prevent leaking.  I hope it works.



 

The Roof

The dream was to make the roof pretty much watertight before Christmas, but it just didn't happen. Too many school and social carol services etc. and wet evenings and weekends left me with bare rafters into the Christmas holiday.

So the noggins needed to be cut and fitted, the frames for the velux windows had to be made and squared and some additional bracing needed to be fitted at the ridge beam.  All of this meant multiple moves of the scaffolding.


Initially I had set it up right across the back of the extension so I could fit the soffitt overhang and fascia.  The new tower was split into two - part indoors and part out with the 4m boards lapped over three sections of scaffolding to make a long run.

Once that was complete I moved it to the drive to finish attaching the rafters to the wall plate using truss clips and angle brackets for the double rafters.  The noggins were all awkward because the gap between the rafters gave too little room either for the drill or for hammering in nails.  Once again every job took three jobs because of moving scaffolding and re-assembling it in the new position.

Once all the structural timber was up I went to Cushions for 11mm OSB3 boards to put on top. Wickes wanted £15 for each board, Cushions' were £9.80 so as I bought 15 I saved £78.  I spent 2 days fastening them to the rafters and taping the seams.  I made the box gulley out of off-cuts from the rafter ends - all cut at 20'.

It needed to slope 2" over the 4m run so it was a matter of lining up first and last, running a string between them and measuring at each rafter then trimming them with the table saw to fit.  It only took a morning and with the OSB cut and screwed down, with a little bit of silicone to seal the end - and a lot of yellow tape along all the edges, it should be water-tight enough until I get the membrane and battens.

I have left the holes for the velux windows covered with the OSB and will simply jigsaw them out when I am ready to fit them.  So now i may be able to get the floor dry enough to lay the final screed.  There are still some little bits of brick/block laying to finish off around the ends of the lintel, along the top of the driveway wall, the old back door and covering the steel post that supports the ridge beam.  I need to work out how many bricks/blocks I need and give a Saturday over to completing so I can do the last bits of insulation and fit the cavity closers.  

The clear-up begins

I ordered an 8-cubic-yard skip, the largest that would take building waste - anything bigger would be too heavy to load onto the truck.

Pips Skips put it exactly where I wanted it and supplied one with a drop-door at the end which is very useful for loading the first couple of tons by barrow.  After that it does need to be closed or it all comes out again.  So from that point onward it all needed lifting over he sides either by bucket or shovel.

If it was hard work digging it out of the ground and throwing it into a pile, it was harder digging it out of the pile, barrowing it round the house and tipping or shovelling it into the skip.  Part of the problem is the rain we have had recently has made it much stickier and heavier.  It was lovely dry sand and soil when I dug it up, now it is heavy mud.

The last bits had a half-way stop on a tarp at the front of the house because I was too tired to load it all in one go.

I had hoped to be able to get rid of all the soil and rubble at the same time, but weight and volume dictated that it wasn't all going to fit, so the soil went.  This has cleared the 3m behind the extension so I can put the scaffolding up and get the soffit & fascia ready for the roof membrane and battens.

In addition to my scaffold tower I managed to buy a second tower through Gumtree.  A lady near halesworth was selling it before she moved house and only wanted £15 for it.  Between my phone call and turning up to collect it she had another 20 calls - I think it will sell well afterwards!

So though the two towers are not compatible, now I can split them to make four bases.  I bought 10 Scaffold Boards (deals) each 3.9m long and have a good working platform outside the extension.  Trouble is now if you want to get to the garden you have to go through the garage, still it should mean that I can get the gable end of the extension ready for the roof membrane, battens, windows and doors.

The plan is to have the extension water-tight by the end of the Christmas holiday, not with the real windows and doors- they will cost something like £4,000 - £5,000 - but with OSB panels cut to size and fastened in temporarily so it can dry out and I can work on the electrics, plumbing, floor and the like, however, until we have the real bifold patio doors on the back I can't really brick-up the old back door because we will still want access out of the back of the house. 

The skip is full and needs to go,but I will have to get a second one at some point to get rid of the brick rubble, and there's bound to be a lot more to go as the project continues.

Mid November update

A couple of things have moved on:

The wall plate I bolted to the parapet wall adjoining Jean's house was only a 4" x 2" timber held by half a dozen sleeve anchors and when I thought about it I decided that I needed something more substantial.  So I removed all the rafters and unbolted the wall-plate.  I cut a couple of lengths of 8" x 2" down to 6" x 2" and drilled it with about 20 bolts.

Once it was on I re-fitted the rafters using galvanised truss clips to locate and secure them.  The rafters are nailed to the ridge plate and spaced equally from the centre point with correct gaps for the 4 velux windows.  Now I need to cut a whole shed-load of noggins to keep the rafters straight and stop them from twisting.

The outside gable end of the extension needs some work to fit the fascia and soffit so I can build the box gulley and lay the roof membrane and battens.  Unfortunately i can't get scaffolding to that end because that is where all the sand/soil/rubble is piled up.  So the next job is to get a skip and clear the space outside the back wall for the scaffold.  The largest I could order to fill with building rubble is 8yd.  I don't think it will be big enough for all the waste, but at least it will clear enough space for the scaffold to move into position and get the roof moved on another stage.

I'm not keen on the short, dark evenings and cold, wet and windy weekends for working on the extension.  I think the chances of getting the roof covered by Christmas are getting slim.

Happy ever rafter

The rafters are 8" x 2" timbers, nominally 14' long (200mm x 50mm x 4200mm) which needed cutting to length and notching at each end to fit over the ridge beam and onto the wall plates.  I cut a piece of timber that had been nailed to the back wall of the house as the wall plate for the old conservatory to make the ridge plate on top of the steel ridge beam.  It needed cutting down from 6" to 4" but was clean and in good condition so it seemed a waste not to use it.


Each rafter needed to be mitred at the end to the 20 degree pitch and then notched to fit the exact distance between the ridge plate and the wall plate.  I started by using my mitre saw, but moving the rafters into position for each cut was difficult without having roller stands to slide them along, so I resorted to clamping them to a pair of trestles and using my old circular saw - which coped well with the 2" depth of cut.  I did have to finish each cut off with a hand saw so that the circular blade didn't over cut any of the lines and weaken the timbers.

At each of the gaps for the velux windows I needed to double the rafters to ensure sufficient strength to support the windows.  The wooden ridge plate and the two wall plates overhang the end wall of the extension so I can build in a 6" soffit overhang above the triangular gable end windows.

These pictures only show the rafters laid on the plates, not adjusted for position or trimmed to ensure they are straight, parallel or at right angles to the walls - all this will come later.

It is interesting to note how much more of a feel for the actual size of the finished room it is possible to get now there is a roof structure.  What would be useful at this point would be a second scaffold tower and/or some wheels for this one as it is difficult to drag and I will need to move it all over the extension to be able to get to every part of the roof structure.  I suppose if I can get a second one I could easily sell it afterwards...

The metalwork is in.

Question: How do you lift a quarter of a ton of steel seven feet up onto the wall?  What's more how do you get a 120kg steel beam twelve feet up and located in the hole in the house, bolted to a post at the other, and make sure it is both straight and level.

Answer:  You hire a Genie SL15 Super Lift with a boom.  it's a great piece of kit (about £3500 worth of great!) that makes the lifting part comparatively easy.  It is a hand-operated winch with extending rail that will take the load to 15 feet.  The hard part is manoeuvring it when it is hanging.  Quarter of a ton of steel, hung from some webbing, seven feet up, is not the easiest thing to place.  However, once the lintel was settled and the post was lightly attached - allowing plenty of adjustment - the ridge beam caused a few problems of its own.

I needed to be in three places at once: operating the lift, locating the bolts into the post, and pushing the end into the hole in the house wall - good job I have long arms and a scaffold tower.

I have to say that in all the moving and locating of the steel the most useful tool I have had has been my car trolley jack.  It will happily lift 2 tons and take the strain of the steelwork.  I used it on the ground to move it initially; then it was priceless up on the scaffold to lift the beam just a few mm to allow it to be slid into the wall.  I don't think I could have managed without it. 


The base of the lintel has had two coats of zinc oxide primer and will have a couple of coats of black gloss to protect it.  It is the only part of the steelwork that will see the light of day.  The ridge beam will be enclosed in the roof timbers, the top and sides of the lintel will be built on and the post will be enclosed in some way.

I'm not sure how to do the post yet.  It is on the inner leaf of the wall, so it would be perfectly possible to install a single window outside it, stretching from one side of the building to the other, however it may be better to build a 30cm wide pillar around the post to encase it and have two smaller, triangular windows instead.

Now the steel is in, the next job will be to attach the wall plates.  The one on the driveway side has been there for a while and is just awaiting the straps being drilled and screwed to the walls to hold it in place.


On the other side the 4" x 2" timber wall plate will be fixed by some 4" sleeve anchors drilled directly through the timber and tightened into the wall.  It is important that I get the wall plate absolutely level as the fall of the box gully depends on the roof being level.  Once this is on I can start cutting rafters and will have a fighting chance of having a roof on by Christmas.

It's a Steel

As the summer holiday ends and term starts there are only a couple of days' block laying left to do before I need to install the structural steelwork,

The combination of the architect's plans and the structural engineer's specifications are sufficient to obtain quotes from steel suppliers around Norwich. As this is an area in which I have no experience I could easily be taken for a ride in terms of price.  I mean, how much is a 6 metre steel lintel?  So I compiled a precis of the specifications and sent it by email to 4 companies to see how close their quotes would be.

Having spoken to one company I was reassured that the quote would be for an approximate length, but they would obviously require accurate measurements for the production.

Three pieces are required:  A lintel that runs almost the entire width of the extension above both the bifold doors and the kitchen window; a ridge beam that comes out from the house to the centre of the back wall, supported by the third piece, a 1.5m post.  All need drilling, welding plates attached and painting - so it's a bit more than just supplying three bits of metal!

I measured both pieces umpteen times before I committed to buy - knowing I can't easily change it once it is welded.  I got 3 quotes and Standley Steel of Wymondham were not only the most competitive, but were genuinely helpful people.

The main lintel over window and doors is 6m long and weighs around 250kg - a quarter of a ton.  it will need lifting 2.1m to put it in place.  The ridge beam, 4.5m long and only about 110kg needs to go another 1.2m above that.  I have a hand-operated crane on order for half term.  

Moving the lintel into the right position for the crane required some ingenuity, planks and rollers, and a car trolley jack.

I cut the hole in the back wall of the house for the ridge beam to sit in and checked it is the right size and depth.


So with the walls ready, the slab floor painted with two coats of bitumen damp proofing, the steel in place and the crane coming on Monday, all we can do now is go to Sheffield to see Ali for the weekend!