Site Clearing a Big Rock

Site clearing for the new Early Childhood Development & Family Centre in Mbuye Sector, Ruhango District (Rwanda). Unfortunately, there is a big rock in the top part of the site, much of which has to be removed. Very slow and strenuous work. Here's a video showing some of the effort. Not too much mechanical equipment (like jack hammers) in Rwanda.

 

Community Engagement Exercise

On June 28^th, we held a community charrette for a new Early Childhood Development and Family Centre in Mbuye Sector, Ruhango District. The event was organized as part of “umaganda”, the monthly day of service that occurs on the last Saturday of every month across Rwanda. We started with two hours of community work to start leveling the site and prepare it for construction. Approximately 300 people, mostly men, showed up to work each with his own shove, hoe, or rake. The architects and myself had already staked out the site and were around to help direct the work as well as lend a hand with the digging. There is about 5 meters of elevation change from the top of the site to the bottom, which is about 25 meters away. The community is going to remove 2.5 meters from one side and add it to the other side before construction starts. The district will hire a contractor to build retaining walls at the top and bottom of the slope and then UNICEF will execute construction of the facility via an agreement with a partner organization.

  

 

 

After site leveling, we gathered for some dancing and then community engagement activities. UNICEF partnered with Imbuto Foundation to assist with these activities and they started by explaining the idea of the Early Childhood Development and Family Centre, which incorporate health, nutrition, and sanitation programmes to benefit young children, their families, and the community at large. When complete, the centres will belong and be operated by the community, with support from UNICEF and Imbuto for training and developing an operating plan.

Once Imbuto explained the goal of the project, the architecture firm ASA described the current design using a wooden model as a visual aid. Since the site provided is long and narrow, the seven buildings will have to be oriented in an S-shape instead of the circular orientation used in areas with larger sites. The idea is to provide three stimulation rooms for the young children (ages 0 to 6), a covered multipurpose room, demonstration kitchen with storage area, an administration building with two offices, and an “ecosan” toilet that separates solids from liquids and uses both as soil amenities. The entire site is fenced in to provide security and children are provided with custom playground equipment. Rainfall from the roofs of all buildings are piped to a 30,000 liter underground masonry tank, similar to what is commonly used for methane digesters.

 

After hearing of the basic design, community members were broken into small groups and given a series of cards showing related images side-by-side. One card for example showed a built-in masonry stove for the kitchen as well as a free standing metal and concrete stove. Other topics included the finishes on the walls (exposed bricks vs. plaster), ground covering for the central courtyard (exposed soil, grass, brick pavers, or gravel), and even the animal they’d like to see incorporated into the design of the slide (elephant vs. cow). The groups were asked to review the two or four pictures on each card, select the one they would most like to see in their ECD&F centre, and fold the card so that image was face-up. All selections were set on the ground when the group was finished and our team walked around taking photos of the selections and the people in the group. Everybody seemed very excited to be able to contribute to the eventual ECD&F design and there was lots of great conversation about what would be best for their children. There were groups of men, women and children participating in a total of approximately 26 groups.

 

 

Once preferences of all groups had been recorded, we explained how the information would be used to improve the ECD&F design and customize it for their preferences. ASA compiled the results to share with the team and will finalize the design based on this feedback. A copy of the results is included below. Many of the results confirmed what we had already assumed, for example 88% of respondents indicated they prefer a built-in masonry stove over a free-standing traditional stove, 92% prefer the latrine to be located far from the front entrance, and 89% would like to have a dedicated water fountain. There were also some results that may necessitate design changes. When asked about preferred landscaping options, the majority of groups preferred brick pavers, which were not included in any of the initial designs. Almost three-fourths of the respondents preferred an option for playground equipment than what we used in this first round of ECD&F construction. Nearly two-thirds of people would rather have a reed ceiling in the stimulation rooms instead of the exposed clay tile roof we’ve been providing. Perhaps most surprising, the majority of groups preferred the S-shaped site orientation over the circular shape because of the feeling of it being more open and inviting. Our initial thought was to always provide the circular shape unless space constraints forced the S-shape. This valuable feedback will help us tailor the design to the local context while also encourage a sense of empowerment and ownership to the community.

 
The District and Sector officials were extremely happy with the event and took a large group out to a celebratory lunch during which they indicated their excitement about the project and appreciation for employing such a participatory process. We committed to sharing the results of the charrette and having ASA visit the site on a weekly basis to direct the site leveling works. UNICEF and the District representative will visit at least monthly to monitor progress.

Video about Architects for UNICEF Projects in Rwanda

Active Social Architecture (ASA) are architects for the pre-primary schools and early childhood development centers I've been managing for UNICEF. As part of an exhibit in Milan, they had this video made. The videographer only had a few days to shoot, none of the ECDs were complete yet, weather was bad, and they didn't get UNICEF permission (which is why they're not mentioned), but the video is really good. Shows off construction techniques in rural Rwanda. Brick masonry buildings with corrugated metal (pre-primary) or clay tile (ECD) roofs. I'm in the background a couple of times.

Video by What Took You So Long:  https://vimeo.com/89417328 

Quality Control - Fired Brick Masonry

Working on early childhood development centers in Rwanda has had me inspecting a lot of masonry construction. There was very little quality assurance put in place when the projects began, so for the most part it has been regular inspections, identifying mistakes, demolishing parts of walls, and re-building correctly. Going forward, a robust total quality management plan will be introduced form the beginning, complete with minimum qualifications, written instructions and signage, assigned people responsible for quality, checklists (pre-construction, during construction, and post), mock-ups, etc. Here are some of the most common errors.

 

 

This wall shows what is supposed to be a Flemish bond, but the header bricks (the single brick running perpendicular to the wall) are cut. The masons do this because the dimensions are bad / inconsistent. If they put the headers in so they are flush with the outside of the building, then there are large divots on the inside where the brick isn't long enough. Ideally, the bricks would be long enough to be flush on the inside and outside (as long as two brick widths plus mortar). We've asked them to pre-select the longest bricks and use them for headers and then to center the headers so there is a small divot on either side. Once Identified as a problem, I prepared signage to have on sites as a teaching tool / prompt, but more needed to happen at the beginning of construction.

 

Another common mistake is bad grout. We're getting very inconsistent mixes (bricks can often be easily removed from walls after the grout is dry). One reason is nobody uses lime, so it is just a small amount of cement and some very dirty sand (often not river sand and they haven't been washing). Regardless of the mix, instead of 1 cm mortar joints, we're seeing as much as 5 cm. This is partly because of un-skilled / un-trained masons, but also because of bricks with different dimensions than assumed by the architects. The architects have shown every single brick in their drawings and when foremen see a certain number of rows of brick under the window sill with specific dimensions given, they are increasing the amount of mortar per row to get the bricks to the level shown on the plans. Going forward, we need to clarify that the mortar joint dimensions are critical (1 cm) and that heights and number of brick courses shown on the drawings for some items, like window heights, have some flexibility.

 

Finally, the rebar in masonry buttresses and columns is new for most masons and we've seen lots of problems. Ideally, the two rebar are spaced 10 cm apart, centered over the buttress or column, and the bricks are woven between the rebar. We're getting rebar poorly set in the foundation, so getting bricks between them / incorporating them into buttresses is difficult. Often, the masons will push the two rebar together and treat them as one because it is easier to lay brick around, though much less structurally secure. Even when it is pointed out that rebar are in the wrong position within a column foundation, we have seen the masons bend the rebar at the bottom to get them where they should be so the entire column becomes wobbly as there is slack in the rebar (and the grout isn't very sticky). 



Evaluating Natural Daylight Levels

After visiting one of our new early childhood development sites, we noticed the inside of the stimulation rooms (classrooms) were a little dark. They buildings are supposed to be naturally daylit, but nobody on the design team knew anything about estimating daylight or optimizing the design. Subsequently, I’ve reviewed the design and taken light levels in the field. My initial conclusion was that the light levels in the center of the rooms at the floor level often met or exceeded recommended levels (primarily because the windows extend very low to the floor below typical vision glazing and light reaches this spot from multiple directions), but at 1 meter off the floor and in many of the corners the levels were below recommended levels. The Illuminating Engineers Society (IES) recommends 50 foot candles (500 lux) on the writing surface for schools for visual comfort and productivity. Based on the 4 sites I measured, the levels with full sun are typically:

 

 

20 - 30 FC in centre of room at 1 meter

60 - 80 FC in centre of room at floor

5 - 10 FC on bench in “front” of room

 

With these light levels, activities low to the ground in the center of the room (building is designed for children 0 - 6) will be well lit with daylight on sunny days and most overcast days, but children in the corners of the room will have less light than ideal. While a couple of the sites have electric lights available to help alleviate this condition (two, 13 watt CFLs without a fixture), we should advise teachers in all sites to focus art projects, reading, and other visually sensitive tasks away from the bench area.

 

There are a number of potential ways to improve the lighting levels if doing a re-design, as well as some options to improve levels in the already constructed buildings. We decided to go with painting the interior brick white to improve reflectance. Each site has three stimulation rooms so we painted the two longest walls white from floor to ceiling in two of the rooms at one site and re-did our testing. Light levels were almost double in the painted rooms and significantly improved light levels. All sites have since been painted (some not yet to the ceiling as in the image below). While the bench area is still darker than is ideal, the rooms are much improved as a result. At other sites that are nearing the end of construction, we're going to remove some of the brick vent holes at top of the front wall and replace with a framed, translucent plastic window, which should bring the daylight levels up to recommended levels.

 

The lesson learned in this exercise is that daylight modeling or at least crude daylight factor calculations are critical for buildings intended to be naturally lit.

 

 

Extra info (sent to my supervisor when trying to raise the issue):

 

An easy way to evaluate natural lighting is daylight factor (DF), which is the ratio of outside illuminance over inside illuminance, expressed in per cent. The higher the DF, the more natural light is available in the room.

 

The general rule is a room needs to achieve at least 2% DF to be considered daylit, though this is still considered gloomy and electric lighting is needed most of the day. From 2 to 5% the daylighting is better, but electric lighting is still needed up until 5% for optimal visual comfort.

 

Using the crudest rule of thumb method of estimating daylight factor (DF = 0.1 * Glazing Area / Floor Area), it looks like we would just be above the 2% “daylit” threshold as we get 2.7% DF (13.7 m2 glazing / 50.8 m2 floor). Unfortunately, this is overly optimistic in our case for a number of reason. Daylight factor is the sum of three components: direct lighting component (DC), externally reflected lighting component (ERC), and internally reflected lighting component (IRC) such that DF = DC + ERC + IRC. The rule of thumb metrics assume typical office building values for all variables. There are a few problems with this method as we need to account for:

 

• Many of the windows and one door are shaded from most direct sunlight by roofs above
• All of the masonry vent openings are deeper (22 cm) than they are tall (8 cm) so let in no direct sunlight most of the day
• Most interior surfaces are dark and non-reflective and standard calculations assume partially reflective white ceilings and light colored interiors

 

As a result, most of our windows and openings have 0 direct lighting component because of the overhangs (good for avoiding heat gain, but also less visible light), we have very little externally reflected daylight since there are no surrounding buildings other than the others we’ve built with non-reflective exterior surfaces, and we have little internally reflected lighting as our interior materials (especially the ceiling) are darker and less reflective than a typical office. We do have the benefit of very clear glazing in the windows with higher than typical visual transmittance (VT) and of course no glazing in the ventilation openings.

 

Multiple field measurements on the overcast day in Site A showed a range of 1% to 2% DF in the center at 1 meter and about 2.5% to 5% DF in the center on the floor. DF calculations at other sites were not possible as it needs to be overcast and low enough direct sun levels to not overload the meter, but they confirmed the Site B assessment by showing full sun measurements in line with what was expected. 

 

To get up to the 5% daylight factor for the entire room (suggested target), we’d ideally incorporate a combination of increased opening size, especially up high where the contribution to daylight factor is greater, and lighter and more reflective interior surfaces. Even adding the colored paint in the current rooms has already brightened the space a lot compared to the pre-painted condition. We’ll see the impact of the white walls in Site A.