Focus group discussions
During discussions with community members, it became apparent that participants understood that smooth, hard floors play an important role in a house, from making it easier to keep clean, strengthening the house, adding aesthetic appeal to the house, and even preventing some diseases.
Female #1: having hard floor keeps my house to be strong, Female #2: it makes my house look good and clean and prevent some ants. Female #3: {it also beautifies} the house makes it easy to clean the house. Male #1: I think it prevent us from getting diseases or infections.
Three traditional procedures of hardening floors were mentioned by participants in all of the six FGDs: (1) use of fire ash mixed with clay soil and water, (2) mixing clay soil with cow dung and termite mound soil or (3) actually building on top of a termite mound. However, it was also noted that only one family in the area is known to use cow dung for building. Participants mentioned that it is a method they have heard of being used by pastoralists such as the Maasai and Borana in other parts of the country. It was highlighted that cow dung is not used in the local cultural context as people feel it is unhygienic and think it would give the house a bad smell. It was also noted that the community used to build on top of old, abandoned termite mounds in the past when their settlements were further inland some decades ago. These days, termite mound soil is still occasionally used but not frequently since these mounds are not common in the study area. Now most households attempting to harden the floor are simply using what they call “clay soil”, sub-soil obtained from their own land or from that of their neighbours and mixed with water.
In response to the question why traditional methods such as the use of termite mound soil, ash and clay and cow dung mixtures are no longer used, respondents noted “we are now in the digital world…also negligence has led us not to practice the traditional way of making floors, everybody (wants) good floors like tiles. It was also mentioned that “lack of knowledge and expertise has contributed”. Regarding cow dung: “it’s unhygienic and very dirty, the smell can make someone feel irritated”.
When asked about who makes and cares for the floors, all respondents reported that it is mainly women and children who make the traditional clay soil floors. A few mentioned men may be involved, or someone may be employed to do it, or even a group of 3–5 people may work together to do it, depending on the size of the house. If a family pays an outsider to make the floor, the cost mentioned ranged from USD 2–10 (Kenya Shillings 200–1000) a day, but many mentioned that instead of paying in cash, they prefer to provide a special meal.
Males: “the (traditional) floor is being made by women with the help of their children, one who has enough funds can employ someone to do it for him or her while in some communities they call for communal help”.
Females: “it also depends, some pay them on an exchange of a meal or cash basis for labour”.
According to respondents, their “clay soil” floors need to be sprinkled with water 2–3 times a week to keep the dust down. After some time, cracks appear in the floor, and they need to be filled with more of the same clay soil and water mix. An extra layer of clay soil may be added onto the whole floor. All respondents reported that the floors quickly become dusty and must be swept 1–3 times a day depending on their condition to remove the dust. Over time this means that material is removed from the floor, lowering its level and undermining the walls, which in time causes them to collapse. One female youth mentioned that their dusty floors expose them to diseases.
Males #1: “If the floor has stayed for so long you may now find some cracks. #3: If the floor was made of clay, you will find after some time it gets loose and become dusty. #6: Through continuous sweeping or cleaning it can weaken the house, which may lead the house to fall down”.
Female youth: “it becomes dusty when not watered and hardened which can cause diseases and infections”.
Floor development
All soil samples from the coastal villages could be described as almost entirely coarse-grained sand with a very low clay content. This included those soils the community referred to as a “clay soil” which they excavate from 1 metre below the surface for construction of their house walls. This composition dictated the range of soil stabilization methods that could be tested in small slabs.
Due to the unavailability of a large enough covered enclosure for the slab tests in the study area, they had to be done outdoors. During the testing period the area experienced unusually high rainfall (Additional File 2 [20]) and flooding of some test slabs which likely prevented them from hardening properly, such as #1, 9 and 10 and led to the poor performance in the tests (Table 2).
Most test slabs performed well in the load-bearing strength test, except slabs #9 and #10 which were made with silicate. A high weight impact chipped the surface of most floors but never cracked them. The abrasion tests left only slight marks on most floors except on slabs #2, #3 and #4. Most of the slabs absorbed at least some of the water after 10 minutes, except for slabs #2 and #3. Two test slabs reached the maximum test score of 12 on the scale (i.e. the worst) at the 8-day tests, slabs #9 and #10, which both did not contain any cement for stabilisation (Table 1). These two slabs were not tested again. The lowest test scores indicate the best floors, which were slabs #2, #3, #5, and #11 all with overall scores after 28 days below 8. However, the material cost estimate of USD 2/ m2 was the lowest for slab #11 so the study team selected the composition of slab #11 to go forward in the pilot field trial. This slab had a base layer of 10 cm and a floor layer of 5 cm and comprised of local subsoil mixed with cement in a 1:9 ratio.
Table 1
Outdoor floor slab composition
| Depths (cm) | Composition of Top Layer (litres) |
Slab number | Base layer compressed | Top layer depth | Cement | Local Subsoil | Water | Building Sand | Coconut fibre compressed | Dabaso soil | Ant hill soil | Fire Ash | Cow dung | Lime | Alkali | Sodium Silicate | Caustic | small stones | Hardcore in base layer (cm) |
1 | | 15 | 45 | - | 30 | 225 | | | | | | | | | | | 15 |
2 | 15 | 15 | 45 | 225 | 30 | | | | | | | | | | | | |
3 | 15 | 15 | 45 | 240 | 30 | | | | | | | | | | | | |
4 | 10 | 10 | 22.5 | 150 | - | | 1 | | | | | | | | | | |
5 | 10 | 10 | 22.5 | - | 20 | | | 150 | | | | | | | | | |
6 | 10 | 5 | 15 | - | 15 | | | | 56 | | | | | | | | |
7 | 10 | 5 | 15 | 75 | 22 | | | | | 7.5 | | | | | | | |
8 | 10 | 5 | 22.5 | 150 | 10 | | | | | | 15 | | | | | | |
9 | 10 | 5 | - | 75 | - | | | | | | | 0.2 | 15 | 10.5 | 4.5 | | |
10 | 10 | 5 | - | 75 | - | | | | | | | 5.3 | 15 | 10.5 | 4.5 | | |
11 | 10 | 5 | 7.5 | 75 | 10 | | | | | | | | | | | | |
12 | 10 | 5 | 7.5 | 75 | 20 | | | | | 7.5 | 7.5 | | | | | | |
13 | 10 | 5 | 7.5 | 75 | 20 | | | | | | | 7.5 | | | | | |
14 | 10 | 5 | 15 | 75 | 20 | | | | | | | | | | | | |
15 | 10 | 5 | 15 | - | 10 | 75 | | | | | | | | | | 30 | |
Table 2
Outdoor floor slab test results and costs
| 8-day RESULTS | 28-day RESULTS | | Costings |
Slab ID | Load bearing | Weight impact | Abrasion | water absorption | Total score | Load bearing | Weight impact | Abrasion | water absorption | Total score | overall score | Material costs (KES) | Labour (KES) | Total cost of slab (KES) | Total cost/m2 (KES) | Total cost/m2 (USD)a |
1 | 1 | 3 | 2 | 3 | 9 | 1 | 3 | 1 | 2 | 7 | 16 | 2154 | 250 | 2404 | 1202 | 11.9 |
2 | 0 | 3 | 0 | 0 | 3 | 0 | 0 | 1 | 2 | 3 | 6 | 804 | 250 | 1054 | 527 | 5.2 |
3 | 0 | 3 | 0 | 0 | 3 | 0 | 1 | 1 | 0 | 2 | 5 | 804 | 250 | 1054 | 527 | 5.2 |
4 | 0 | 2 | 0 | 3 | 5 | 0 | 1 | 1 | 3 | 5 | 10 | 502 | 250 | 752 | 376 | 3.7 |
5 | 0 | 1 | 1 | 0 | 2 | 0 | 1 | 1 | 3 | 5 | 7 | 602 | 250 | 852 | 426 | 4.2 |
6 | 0 | 3 | 1 | 2 | 6 | 0 | 2 | 0 | 3 | 5 | 11 | 465 | 250 | 715 | 357 | 3.5 |
7 | 0 | 1 | 1 | 2 | 4 | 0 | 3 | 1 | 3 | 7 | 11 | 268 | 250 | 518 | 259 | 2.6 |
8A | 0 | 2 | 1 | 3 | 6 | 0 | 1 | 1 | 3 | 5 | 11 | 402 | 250 | 652 | 326 | 3.2 |
8B | 0 | 2 | 1 | 3 | 6 | 0 | 0 | 0 | 3 | 3 | 9 | 402 | 250 | 652 | 326 | 3.2 |
9 | 3 | 3 | 3 | 3 | 12 | nd | nd | nd | nd | nd | nd | 961 | 250 | 1211 | 605 | 6.0 |
10 | 3 | 3 | 3 | 3 | 12 | nd | nd | nd | nd | nd | nd | 1198 | 250 | 1448 | 724 | 7.2 |
11 | 0 | 2 | 1 | 1 | 4 | 0 | 1 | 1 | 1 | 3 | 7 | 134 | 250 | 384 | 192 | 1.9 |
12 | 0 | 2 | 1 | 3 | 6 | 0 | 1 | 1 | 3 | 5 | 11 | 134 | 250 | 384 | 192 | 1.9 |
13 | 0 | 3 | 1 | 1 | 5 | 0 | 2 | 1 | 3 | 6 | 11 | 483 | 250 | 733 | 366 | 3.6 |
14 | 0 | 1 | 1 | 3 | 5 | 0 | 0 | 1 | 3 | 4 | 9 | 268 | 250 | 518 | 259 | 2.6 |
15 | 0 | 1 | 1 | 2 | 4 | 0 | 3 | 1 | 3 | 7 | 11 | 1018 | 250 | 1268 | 634 | 6.3 |
a Exchange rate Dec 2019 1 USD = 101.2 KES nd: not done |
Pilot field trial
Floor installation. The floors were installed by two teams each comprising one trained mason and one labourer, one team installing concrete floors and the other installing the low-cost floor. For some of those households who had a young man in the family, he would also assist with the manual labour, but this was not required of them. Families provided all the water that was needed. The concrete floors took one a half to two days to complete while the low-cost floor took only one day for the small house size of around 30 m2. Although families were asked to empty all belonging from the houses ahead of time, often they had not done so when the masons arrived, delaying the floor installation. Families usually had other family members living nearby with whom they could stay and store items while they had to be out of their own house. A major challenge was families not complying with the daily water sprinkling and the instruction to stay out of the house for seven days. Although routine checks were not included in the protocol, occasional spot checks revealed most families returned to the house after three days.
Characteristics of households and retention of participants. A total of 36 households, occupied by 69 adults (over 17 years) and 141 children, were enrolled and randomized to the three study arms as illustrated in the study flow chart (Fig. 3). Seven of the 36 enrolled houses were improved semi-permanent houses having stone brick walls with cement and an iron sheet roof, but with an unsealed earthen floor. Four of these seven houses received a floor. The other 29 houses had walls of either palm leaf, mud in a wood frame or mixed mud and rough stones in a wood frame combined with either a palm leaf or iron sheet roof as previously illustrated in Fig. 1. Only children aged 17 years and under who were infected at baseline, were enrolled as participants for follow-up evaluation of outcome measures. A total of 135 infected children were enrolled at baseline, ranging between 2 and 5 per household (median 4, IQR 3–4). There were 12 households with 45 infected children in the control group and 24 households with 90 infected children in the intervention groups. Over the course of the study, four (11%) complete households with 16 participants were lost to follow up due to either the house falling or burning down (n = 3), or the family moving away (n = 1). For the analysis a further 1 household and a total of 9 participants were excluded from the analyses due to having incomplete data sets. The final full data sets for analyses included 9 households with 31 children in the control group and 22 households with 79 children in the intervention group (Fig. 3). Of the 110 children in the analyses, 57% were boys and the average age was 7 years (SD 2.0, range 3 to 12 years).
INSERT FIGURE 3 HERE
Figure 3. Study Flow Chart. HH = household, ptps = participants, infected children enrolled at baseline.
At baseline, the household head or caregiver in each participating family was asked what they felt about the floor they currently had. Most of them (n = 32 of 36) said they did not like the earthen floors as; “It is dusty and not pleasant”, “Has dust while sweeping”. A few (n = 6) associated these floors with tungiasis infection “Floor is dusty which I believe brings jiggers”, others with flies (n = 5) “It is dusty and loose which brings flies” or respiratory illness (n = 3); “Has a lot of dust which causes flu”. Like the participants in the FGDs, the majority of household heads (n = 22) in the trail reported to reduce the dust and harden the floors by pouring water on them daily. Only four said they smeared mud to harden the floor occasionally, and none had used cow-dung. For those who had never tried to harden their floor they stated this was because they couldn’t afford a better floor, “I don’t have money to get a good floor”; did not have the knowledge or skills, “I have no skills to do it”; or they did not have time to do it, “Am always out for work, no time to harden the floor”. All the households had attempted to control the tungiasis in their family by either spraying the house floor with water alone (n = 5) or mixing water with neem (Azadirachta indica) leaf extract (n = 12) or paraffin (n = 2).
Tungiasis infection. At baseline, all enrolled participants were infected according to selection criteria, hence the proportion of participants (prevalence) who were infected was 100%. By midline, the prevalence decreased in both the control and the flooring groups, to 65% in the control group and 47% in the floor group (Table 3). By the end of the study, ten months after floor installation, the prevalence increased again in both study arms to 71% in the control arm and 54% among those with a floor. While the odds of infection among children in the intervention arm was half that for children in the control arm at midline (OR 0.46) and endline (OR 0.49), this did not reach statistical significance at the 0.05 level since the pilot was not sufficiently powered (Table 3).
Table 3
Bivariable model for proportion of participants infected by study arm and time point
Time point | Study arm | Percent | 95% CI1 | OR2 | 95% CI1 | p |
Baseline | Control | 100 | | | | | | |
With floors | 100 | | | | | | |
Midline | Control | 65 | 0.46 | 0.79 | 1 | | | |
With floors | 47 | 0.36 | 0.58 | 0.46 | 0.12 | 1.59 | 0.241 |
Endline | Control | 71 | 0.53 | 0.84 | 1 | | | |
With floors | 54 | 0.43 | 0.65 | 0.49 | 0.11 | 1.86 | 0.320 |
1 confidence interval 2 odds ratio |
Infection intensity and associated symptoms. Infection intensity as well as the associated symptoms as measured by infrared and acute morbidity score were similar at baseline for children in the two study arms (Table 4). By midline, the infected participants’ infection intensity and symptoms had decreased considerably in both study arms. However, for all three outcomes, the reduction in the flooring group was around 40% higher than in the control group, as expressed by the effect sizes in Table 4. At endline, the median infection intensity was back to baseline levels among the control households (median 18 fleas, IQR 9–28) but remained low among participants living in a house with improved a floor (median 8 fleas, IQR 2–14, Table 4). Median infection intensity, median inflammation and acute symptom scores for children in the floor groups were over 50% lower than for those in the control group at endline. Whilst this did not reach statistical significance at the 0.05 level in the bivariate analysis, it did when adjusted for confounders (aIRR 0.53, 95% CI 0.29–0.97, Table 5). There were no interactions between any of the independent variables.
Table 4
Bivariable model for Household median infection intensity, infra-red and acute morbidity for cases by study arm and time point
| | | Infection intensity | Infra-red score | Acute morbidity |
Time point | Study arm | N1 | Median (IQR2) | IRR3 (95% CI4) | Median (IQR) | IRR (95% CI) | Median (IQR) | IRR (95% CI) |
Baseline | Control | 31 | 18 (7–28) | 1 | 6.5 (4–9) | 1 | 13 (8–17) | 1 |
Floors | 79 | 14 (7–29) | 0.90 (0.54–1.50) | 6 (4–9) | 1.07 (0.8–1.45) | 13 (8–20) | 1.07 (0.79–1.44) |
Midline | Control | 20 | 5 (2-12.5) | 1 | 4.5 (1-7.5) | 1 | 7 (3-10.5) | 1 |
Floors | 36 | 3.5 (2–8) | 0.66 (0.29–1.49) | 2 (1–5) | 0.59 (0.26–1.37) | 3 (1-7.5) | 0.55 (0.22–1.39) |
Endline | Control | 22 | 18 (9–28) | 1 | 4 (2–5) | 1 | 8.5 (4–14) | 1 |
Floors | 43 | 8 (2–14) | 0.47 (0.20–1.12) | 2 (0–4) | 0.47 (0.18–1.23) | 4 (1–8) | 0.43 (0.15–1.21) |
1 N: number of participants. 2 interquartile range 3IRR: incidence rate ratio 4 Confidence interval |
Table 5
Bivariable and multivariable regression for infection intensity among cases at the end of the study.
| | | Bivariable | Multivariable |
| | N1 | IRR2 (95% CI3) | P | aIRR4 (95% CI) | P |
Intervention group | control | 31 | 1 | | 1 | |
floor | 79 | 0.47 (0.20–1.12) | 0.089 | 0.53 (0.29–0.97) | 0.039 |
Sex | female | 49 | 1 | | | |
| male | 61 | 1.01 (0.69–1.47) | 0.961 | | |
Age5 | | 110 | 1.00 (0.94–1.06) | 0.904 | | |
Relationship to HHH6 | child | 80 | 1 | | 1 | |
grandchild | 24 | 1.38 (0.66–2.89) | 0.393 | 1.14 (0.57–2.30) | 0.705 |
HHH education level | complete primary | 15 | 1 | | 1 | |
incomplete primary | 68 | 1.15 (0.33–3.93) | 0.828 | 0.28 (0.09–0.90) | 0.032 |
none | 27 | 1.38 (0.37–5.07) | 0.629 | 0.99 (0.38–2.55) | 0.981 |
Religion | christian | 39 | 1 | | 1 | |
| muslim | 6 | 0.09 (0.01–0.98) | 0.048 | 0.16 (0.02–1.25) | 0.082 |
| traditionist | 58 | 1.18 (0.52–2.71) | 0.687 | 1.45 (0.79–2.66) | 0.235 |
Income source | employed | 25 | 1 | | | |
casual labour | 38 | 1.00 (0.31–3.25) | 0.998 | | |
self employed | 26 | 0.97 (0.27–3.51) | 0.966 | | |
selling alcohol | 10 | 1.11 (0.25–4.90) | 0.892 | | |
none | 11 | 1.07 (0.24–4.87) | 0.928 | | |
HHH Marital status | married | 84 | 1 | | | |
single | 26 | 0.99 (0.35–2.75) | 0.977 | | |
Wall material | stone blocks | 32 | 1 | | | |
mud and stone | 26 | 0.53 (0.21–1.39) | 0.197 | | |
mud | 41 | 0.32 (0.12–0.84) | 0.021 | | |
palm leaf | 11 | 0.26 (0.07–0.94) | 0.04 | | |
Roof materials | iron sheet | 53 | 1 | | | |
palm leaf | 57 | 0.40 (0.19–0.87) | 0.021 | | |
Water source | own tap | 9 | 1 | | | |
community tap | 91 | 0.93 (0.21–4.09) | 0.92 | | |
shared well/ borehole | 10 | 1.02 (0.13–7.97) | 0.986 | | |
Toilet type | open defecation | 51 | 1 | | 1 | |
| traditional latrine | 59 | 2.42 (1.09–5.40) | 0.03 | 5.01 (1.98–12.67) | 0.001 |
1 N: number of participants. 2 IRR: incidence rate ratio 3 Confidence interval 4 aIRR: adjusted incidence rate ratio 5 age in years most surveys 6HHH: head of household |
Floor durability and costs. By the end of the study, 12 of 12 low-cost floors had developed fine lines in the finish and one had a larger open crack. Of the concrete floors, 10 out of 12 also had fine lines in the finish. Most fine cracks were observed around the edges of the floor where it joined the wall, particularly in houses where the residents had replaced or repaired the walls. From the four tests conducted on the floors, neither the 100 kg weight nor the weight drop had any impact on either the concrete or the low-cost floor (Additional file 2). However, some of the new floors were impacted slightly by the abrasion test (median score 1) and seemed to absorb some water in the permeability test (median score of 2).
The average house size in the study was 30 m2, ranging from 8 m2 to 94 m2. The only costs for the new low-cost floor were for cement, transport of materials and workmen and the local labour charges since the sub-soil was taken directly from the plot. The total cost of installing the soil-stabilised floor for the average house size was US$115 ($3.9/m2) (Table 6). For the concrete floor there was the additional cost of ballast, hardcore and river sand and transporting these with a truck from a local supplier. The concrete floors for the average house size cost a total ofUS$278, an average of US$9.3/ m2.
Table 6
Costs for the installation of the floors in an average house of 30m2 during the pilot study. (Exchange rate at the time, December 2019 0.0097)
| Item | Units | No. of Units | Unit Cost US$ | Total Cost US$ |
Low-cost floor | Cement | bag | 6 | 6.3 | 37.8 |
Transport | day | 1 | 9.7 | 9.7 |
Labour | pax | 2 | 34.0 | 67.9 |
Total | | | | 115.4 |
Total per m2 | | | | 3.9 |
Local concrete floor | Cement | bag | 8 | 6.3 | 50.4 |
River sand | tonne | 4 | 17.5 | 69.8 |
Ballast | tonne | 2 | 24.3 | 48.5 |
Hardcore | tonne | 2 | 14.6 | 21.8 |
Transport | day | 2 | 9.7 | 19.4 |
Labour | pax | 2 | 34.0 | 67.9 |
Total | | | | 277.9 |
Total per m2 | | | | 9.3 |
Community perception of improved floors. At the end of the study one adult from each of 32 houses that participated till the end, was asked their opinion about their new floor (11 with concrete floor and 12 with a low-cost floor). Everyone with the concrete floor (11) and 10 of those with the low-cost floor (10/12) said they were satisfied with it. The two households who indicated that they did not like the low-cost floor reasoned that “some part of the living room [have] some cracks” and “in the sitting room the surface is flacking…there is small hole which allows some ants penetrate through and have some cracks”.
Those who received the concrete and low-cost floor had very similar reasons for liking the floor. The most common reasons being it was much easier to clean (13 of 20), reduced dust (11 of 20), and there were less insects in the house, particularly ants and fleas (9 of 20). “I like it because it reduces the amount of fleas, it’s easy to sweep and clean and less dust in the house”; “my house has no more jiggers”.
Other reasons for approving of the floor were ability to sleep and sit on the floor without getting dirty and aesthetics; “my kids are not getting dirty anymore”; “my children can now sit down on the floor and study”; “it makes my house very clean and smart”. One person also felt the floor protects from respiratory illness “kids are not infected with flu”
Some respondents from houses with the concrete floor, but none from houses with the low-cost floor mentioned that it made their house stronger (6 of 11 houses): “it is long lasting it has strengthened the house”; “it has made my house firm”.