diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
new file mode 100644
index 000000000..f9bdc8bbf
--- /dev/null
+++ b/.github/workflows/build.yaml
@@ -0,0 +1,39 @@
+name: Sail CI Build
+
+on:
+  push:
+  pull_request:
+  schedule:
+  - cron: "0 0 * * *"
+
+jobs:
+  full-test:
+    strategy:
+      matrix:
+        os: [ubuntu-20.04, macOS-latest]
+        ocaml: [4.06.1, 4.10.0]
+    runs-on: ${{ matrix.os }} 
+
+    steps:
+      - name: Check out repo
+        uses: actions/checkout@v2
+      - name: Install deps (linux)
+        if: matrix.os == 'ubuntu-20.04'
+        run: sudo apt-get install -y --no-install-recommends build-essential libgmp-dev z3 libz3-dev opam
+      - name: Install deps (macOS)
+        if: matrix.os == 'macOS-latest'
+        run: brew install gpatch gmp z3 pkg-config opam
+      - name: init opam
+        run: opam init -y --no-setup --compiler=${{ matrix.ocaml }} --shell=sh
+      - name: opam config env
+        run: eval `opam config env`
+      - name: pin and install sail from git
+        run: opam pin -y add sail $PWD
+      - name: test sail installation
+        run: eval $(opam env) && sail -v
+
+      - name: make sail-arm
+        run: git clone https://github.com/rems-project/sail-arm.git && cd sail-arm/arm-v8.5-a && eval $(opam env) && make
+
+      - name: make sail-riscv
+        run: git clone https://github.com/rems-project/sail-riscv.git && eval $(opam env) && make
diff --git a/.github/workflows/macOS_build.yml b/.github/workflows/macOS_build.yml
deleted file mode 100644
index ebc97a632..000000000
--- a/.github/workflows/macOS_build.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-name: CI macOS-latest
-
-on: [push]
-
-jobs:
-  build:
-
-    runs-on: macOS-latest
-
-    steps:
-    - uses: actions/checkout@v1
-    - name: Build on macOS
-      run: |
-        brew install gpatch gmp z3 pkg-config
-        brew install opam
-        etc/ci_opam_build.sh
diff --git a/.github/workflows/ubuntu_18_04_build.yml b/.github/workflows/ubuntu_18_04_build.yml
deleted file mode 100644
index ada366b42..000000000
--- a/.github/workflows/ubuntu_18_04_build.yml
+++ /dev/null
@@ -1,18 +0,0 @@
-name: CI ubuntu-18.04
-
-on: [push]
-
-jobs:
-  build:
-
-    runs-on: ubuntu-18.04
-
-    steps:
-    - uses: actions/checkout@v1
-    - name: Build on ubuntu
-      run: |
-        sudo add-apt-repository ppa:avsm/ppa
-        sudo apt update
-        sudo apt install build-essential libgmp-dev z3 m4
-        sudo apt install opam
-        etc/ci_opam_build.sh
diff --git a/.github/workflows/ubuntu_20_04_build.yml b/.github/workflows/ubuntu_20_04_build.yml
deleted file mode 100644
index 097b56bff..000000000
--- a/.github/workflows/ubuntu_20_04_build.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-name: CI ubuntu-20.04
-
-on: [push]
-
-jobs:
-  build:
-
-    runs-on: ubuntu-20.04
-
-    steps:
-    - uses: actions/checkout@v1
-    - name: Build on ubuntu
-      run: |
-        sudo apt install build-essential libgmp-dev z3
-        sudo apt install opam
-        etc/ci_opam_build.sh
diff --git a/.github/workflows/ubuntu_20_04_build_latest.yml b/.github/workflows/ubuntu_20_04_build_latest.yml
deleted file mode 100644
index 4e9158d75..000000000
--- a/.github/workflows/ubuntu_20_04_build_latest.yml
+++ /dev/null
@@ -1,16 +0,0 @@
-name: CI ubuntu-20.04 (ocaml latest)
-
-on: [push]
-
-jobs:
-  build:
-
-    runs-on: ubuntu-20.04
-
-    steps:
-    - uses: actions/checkout@v1
-    - name: Build on ubuntu (ocaml latest)
-      run: |
-        sudo apt install build-essential libgmp-dev z3
-        sudo apt install opam
-        etc/ci_opam_latest_build.sh
diff --git a/etc/ci_opam_build.sh b/etc/ci_opam_build.sh
deleted file mode 100755
index 10af3e3c2..000000000
--- a/etc/ci_opam_build.sh
+++ /dev/null
@@ -1,12 +0,0 @@
-#!/bin/sh
-
-set -eu
-
-opam init -y --no-setup --compiler=4.06.1 --shell=sh
-
-eval `opam config env`
-
-opam repository -y add rems https://github.com/rems-project/opam-repository.git
-opam pin -y add sail .
-opam install -y -v sail
-sail -v
diff --git a/etc/ci_opam_latest_build.sh b/etc/ci_opam_latest_build.sh
deleted file mode 100755
index 9e994b229..000000000
--- a/etc/ci_opam_latest_build.sh
+++ /dev/null
@@ -1,12 +0,0 @@
-#!/bin/sh
-
-set -eu
-
-opam init -y --no-setup --compiler=4.10.0 --shell=sh
-
-eval `opam config env`
-
-opam repository -y add rems https://github.com/rems-project/opam-repository.git
-opam pin -y add sail .
-opam install -y -v sail
-sail -v