A New Roof and 5 Construction Insights

I (David) have learned many things since coming to South Sudan.  One lesson I've learned is this – water-proofing and bug-proofing a house is a very big task!  Over the past 7 months we have built 2 new prefab houses and 1 new concrete house.  Unfortunately still today none of these houses are “perfect”.  What else have I learned?

#1 Prefabs are not "weather proof" structures (even though the manufacturers website claims they are).

You can read more about my previous recommended best practices in building a prefab linked here.  I can now confidently say that you can try very hard and spend a lot of time/money on silicone caulking, waterproofing bituminous tar, but the prefab will still not be perfectly watertight during the rainy season.  This lead my teammates and I to decide we would build a secondary roof over the each of the prefabs.

Front view (before)

Front view (after)

Back view (before)

Back view (after)

#2 Work with contractors you trust and know.

I knew this in Canada and its common sense.  Neighbouring NGOs had hired a man named George to work for them and then prior to my arrival my teammates had hired him to weld some windows and doors on campus.  With those recommendations we obtained a price from George for the work to complete the roofs.  He was the only “bidder” (which isn’t ideal) but I was able to bargain with him to get a reduced price.  His first price was 18,000 South Sudanese Pounds (around $4,000).  But when we figured out that the work should take 25 days and when I said I thought the cost should be around 7,000 SSP, we finally agreed on a final price of 9,000 SSP (around $2,000).  So we signed the contract (linked here) on Saturday July 13 and he showed up on Monday July 15 with his work crew.  The contract is nothing like the 45 page legal CCDC contracts I'm used to seeing in Canada (which also have 100s of pages of specifications and drawings attached).  Here it was a simple 2 pages that said "construct according to the drawings provided that may change from time to time" :)

#3 Buying materials is expensive and getting them to your construction site is not easy!

It is not uncommon in South Sudan to sign a labour-only contract (which is what we did in the case of the roofs).  As a result, it was my responsibility to find cement, gravel, sand, zinc roofing sheets, roofing fasteners, welding rods, and steel support members.  Fortunately we had sand, some steel and roofing sheets already on campus.  I was able to buy welding rods in the local Melut market, but getting cement, gravel and roofing fasteners was a different story.  For cement I had to travel by boat up the Nile River 30 minutes to a nearby town of Kaka.  There I paid 250 SSP ($60) per bag of cement – way too expensive!! The non-rainy season price should be around 150 or 180 SSP per bag.

It also worked out that I was already planning a boat trip (linked here) to the state capital of Malakal. While I was there I loaded up a horse cart with more roofing sheets, more steel, some PVC piping for rain gutters and 2000 roofing fasteners. My job of finding materials was complete.

A box of 250-2" self drilling screws.  This box cost me 400 SSP (about $0.50 per screw).

#4 Good contractors can stay on schedule (and even finish ahead of schedule)

As I said we had agreed on a 25 day schedule and George and his men started on Monday July 15 and worked 6 days a week (Mon-Sat).  Yesterday (August 3) after only 18 days of work they were finished all of the work.  Not bad eh?

#5 Good contractors still need to be reminded of “best practices”

There were a few times that I would check in on the guys working and one of the times I had to remind them to secure the roofing fasteners in the “top grooves” of the zinc sheets (not in the valleys).  It’s obviously easier to screw into the valleys but the valleys are where all of the water drains.  So after I explained that the roof would be less susceptible to water penetration if the fasteners were not in the valleys the guys agreed.

5 of the 6 fasteners in the bottom row are in the valleys (the wrong spot).  After I told them why they should not be in the valleys they got much better!

Here are a few photos of the progress.  Enjoy!

Steel frame completed at the Cross' prefab.  At both prefabs the support posts are spaced at a maximum of 3.5m.

4.2m long zinc roofing sheets were used here with 4 purlins on each side (spaced at 1.35m)

Our prefab before we added the "post extensions".  You can see our bamboo canopy still in place on the front facing the river.  It was a temporary 3 month solution to provide shade and it was good while it lasted.

 

The first roof was completed and you can see George welding our trusses in place

We were able to reuse a lot of the existing posts by simply adding 40mmx80mm steel tube extensions.

3.6m long zinc roofing sheets were used on our roof with 3 purlins on each side (spaced at 1.75m)