The Day of the Trusses

It's the 21st and at 8am this morning the trusses arrived on the low loader...

in fact they came on two trucks....

and blocked part of the road for a couple of hours. 

The builders relied on George the crane driver again to lift the trusses from the big low loader truck and take them up the driveway.

The trusses were moved to the top of the driveway temporarily. It took about 3 hours of hard work for all the sections to be lifted off the truck and placed on the driveway. 

The next step is to crane them over the scaffolding and onto the wall plate. Each one will then be dragged along to its final position.... and that's when the builders will have some issues to solve...

The Building Work Starts

The Building Work Starts

we've been away for the last week and in this time the project has moved from demolition to building work.

The front wall of the house has been rebuild with new window and door openings.

The steel beam has also been put in place on two newly created pillars for the bi-fold doors in the back of the house.

It's a little bit bigger than the builder expected - better to be over engineered than under...

that's Phil's shoe to show the scale of the beam.

The new window has also been formed in the games room.

And the new lintels put in place above the existing windows.

So now the house is ready for the trusses to arrive. The delivery is scheduled for Thursday 21st.

and the walls came tumbling down...

and the walls came tumbling down...

another day brings more walls down... not that i was really expecting these ones to come down completely!

the builders decided that it was simpler to knock the walls down at the front of the house and then rebuild them. here they are starting on the kitchen end of the house.

the end result was a hole in the front of the house.

they also removed the back wall and the bi-fold doors

so now we have a house of two halves - literally! there is now nothing in the middle!

after the builders had gone today the crane driver, George, came round. He wanted to check on the access to the house for the crane and the lorry carrying the trusses.

As the large articulated lorry cannot get up the drive it was decided to load the trusses onto a normal rigid bed truck. Normally this wouldn't have been an issue... until today that is. It turns out that the rigid bed truck is higher than the low loader arctic lorry... this combined with the height of the trusses means they are now going to be higher than the max height permitted on UK roads!

So, (he says with a smile), the upshot is the trusses will have to be transported once again on the low loader. This will have to park somewhere outside the house on the road and the crane driver and builders are now going to have to man handle, with the aid of a small, mobile crane, the trusses up the drive an onto the front grass. From there the crane driver, using a bigger crane...

will then lift each truss into place. Sounds simple...?!

What a difference a day makes...

What a difference a day makes...

Day 19...

So this time yesterday we were looking through websites and files to try and resolve the issues that had cropped up, the main one being the size of the steel beam and the amount of deflection and it's impact not he bi-fold doors. 

We were also slightly concerned that the lead times for the roof trusses had gone out to 6-7 weeks. The impact of this was that the builders might well run out of things to do int he house before the trusses arrived on site.

A day later and things have improved - Hooray!

I talked to the surveyor Matt this morning and he talked me through his rationale for the bi-fold doors and the steel beam. The technical bit comes next, so if you don't want to read this then you best jump down the page now.

The load on the beam is made up of two parts - the Dead Load and the Live Load. The Dead Load is the weight of the roof structure with everything in it. The engineer had specified the beam and calculated that the Dead Load deflection for the beam, based on it spanning a 6.5 metre gap, would be 3mm in the centre.

The Live load is the loading that could occur if extra weight was added. Like snow on the roof or people. The calculation for this suggests a deflection of around 5mm. So in total we could theoretically see a deflection of around 8mm.

BUT... he told me that the door manufacturer would only measure the window size once the roof was loaded and so would accommodate the 3mm Dead Load deflection in the door height. So we would then only have to content with the 5mm deflection - which the doors should be able to handle. the upshot of this is that we can safely fit the bi-fold doors without having to install a central support.

You can read on from here if you didn't want the tech bit...

At the same time i was talking with the surveyor Claire talked to the builder. He told her that he had to order the beam today. She questioned him about his timing. He told here that, having now spoken again to the truss manufacturer, they have said the trusses could be here in... 2 weeks! A big change from the original 5-7 weeks. So that's a big hooray!

He also told her about the doors. When he rang the steel company to order the beam and gave the measurements the guy on the end of the phone laughed. The beam that has been spec'd is 356X171x67 (roughly 363.4mm deep x 173.2 wide and weighing around 67KG per metre.) The overall beam will be about 7.5 metre long.

He laughed because he said 'what are you trying to prop up - the whole village'. Typically it seems the surveyor and structural engineer had 'over-spec'd' the beam - probably just to be safe.

I think Claire wanted to hug the builder when he told her this as she was really concerned we'd have a pillar in the middle.

the other work completed today was the removal of the pitch brick work above the old patio door.

And the removal of the bi-fold doors. If anyone wants these they better let me know ASAP - otherwise they'll go on eBay...

So that's the good news today.

Week 4 & We are hitting a few design issues

Week 4

We are hitting a few design issues... already.

firstly we had to confirm the roof truss size and specification - i thought that this had been agreed with the truss company by the surveyor. more on that later

secondly, now we have had a more detailed insight into the truss design it appears that the new section will have 200mm joists. which normally would be fine - but we have decided to leave the existing roof structure on the games room area of the house. The problem? the old section of house only has 120mm joists. So somehow we have to come up with a plan to combine the new and old - and make up the 80mm difference.

thirdly, the builder asked me today for the structural engineer calculations. 

These were completed last October and so i thought all issues had been resolved. The main one that has been on my mind since we started the design is the maximum deflection allowable for the bi-fold doors to operate smoothly. the issue being that the designed beam, which is 8 metres long, will deflect by around 8mm in a worst case. I looked on a set of the structural engineers drawings today and noticed that it says that the 'architect was informed' in October.  Somewhere something has gone astray in our communication!

So, the truss sizes and spec has been confirmed and the trusses have been ordered. Trouble is... their lead times have increased to 5 - 7 weeks. (up from 3 weeks when we last spoke to them). So now we are going to hit an issue where the builders run out of things to do before the trusses arrive. The builder has requested the order be marked as urgent... we will wait and see how that works out.

With regards the difference in size. we have two options. the first is to completely remove the existing roof and completely fit new trusses. the issue here is that we have not covered that section of roof with scaffold and based on the assumption that the roof would stay on this section of the house we are now intending on leaving the ceilings intact - hopefully saving some of the budget. So this option doesn't really work.

The second option is to increase the size of the existing trusses. The builder has suggested that each truss be increased in size by attaching extra wood to the top of it. This will work... provided the trusses can actually support the weight. Justin intends to fix two 2x2 battens perpendicular to each other across the whole roof. This will increase the thickness of the overall roof by around 100mm and so should line up with the new trusses... we hope.

Now onto the beam deflection. I am a bit peeved by this as i thought it was all agreed months ago. Basically the surveyor gave me the calcs for the steel beams today. The main steel across the windows is around 8 metres long and spans the 6.5 metre opening. The calculations suggest the beam will sag by unto 8mm in the centre. 

The issue is how much deflection the bi-fold doors will take... my feeling is it will be less than 8mm.

The solution will probably be to add in a central support pillar - not ideal as this is what we wanted to avoid. We will find out more on Friday.

I thought that was all the issues for one week the we spotted another. 

The screed over the UFH in the kitchen looks like it has completely broken down where it has been covered with tile adhesive. So as the builders have been removing the tiles the screed has just crumbled away - revealing the UFH pipes!! Potential disaster waiting to happen. At this stage we think we will have to dig up all the screed, carefully revealing all the pipes and then re-screed the whole area! We will know more in a few days time.

So, after two good weeks of progress we have hit a few little humps in the road. Watch this space for more to follow...