diff --git a/packages/ngtools/webpack/src/compiler_host.ts b/packages/ngtools/webpack/src/compiler_host.ts
index 7ed4d444fe..e11acf71fe 100644
--- a/packages/ngtools/webpack/src/compiler_host.ts
+++ b/packages/ngtools/webpack/src/compiler_host.ts
@@ -74,25 +74,61 @@ export class VirtualDirStats extends VirtualStats {
 
 export class VirtualFileStats extends VirtualStats {
   private _sourceFile: ts.SourceFile | null;
-  constructor(_fileName: string, private _content: string) {
+  private _content: string | null;
+  private _bufferContent: virtualFs.FileBuffer | null;
+
+  constructor(_fileName: string) {
     super(_fileName);
   }
 
-  get content() { return this._content; }
+  static createFromString(_fileName: string, _content: string) {
+    const stats = new VirtualFileStats(_fileName);
+    stats.content = _content;
+
+    return stats;
+  }
+
+  static createFromBuffer(_fileName: string, _buffer: virtualFs.FileBuffer) {
+    const stats = new VirtualFileStats(_fileName);
+    stats.bufferContent = _buffer;
+
+    return stats;
+  }
+
+  get content() {
+    if (!this._content && this.bufferContent) {
+      this._content = virtualFs.fileBufferToString(this.bufferContent);
+    }
+
+    return this._content || '';
+  }
   set content(v: string) {
     this._content = v;
-    this._mtime = new Date();
-    this._sourceFile = null;
+    this._bufferContent = null;
+    this.resetMetadata();
+  }
+
+  get bufferContent() {
+    if (!this._bufferContent && this._content) {
+      this._bufferContent = virtualFs.stringToFileBuffer(this._content);
+    }
+
+    return this._bufferContent || virtualFs.stringToFileBuffer('');
+  }
+  set bufferContent(buf: virtualFs.FileBuffer) {
+    this._bufferContent = buf;
+    this._content = null;
+    this.resetMetadata();
   }
+
   setSourceFile(sourceFile: ts.SourceFile) {
     this._sourceFile = sourceFile;
   }
   getSourceFile(languageVersion: ts.ScriptTarget, setParentNodes: boolean) {
     if (!this._sourceFile) {
-      // console.log(this._path)
       this._sourceFile = ts.createSourceFile(
         workaroundResolve(this._path),
-        this._content,
+        this.content,
         languageVersion,
         setParentNodes);
     }
@@ -100,12 +136,16 @@ export class VirtualFileStats extends VirtualStats {
     return this._sourceFile;
   }
 
+  private resetMetadata(): void {
+    this._mtime = new Date();
+    this._sourceFile = null;
+  }
+
   isFile() { return true; }
 
-  get size() { return this._content.length; }
+  get size() { return this.content.length; }
 }
 
-
 export class WebpackCompilerHost implements ts.CompilerHost {
   private _syncHost: virtualFs.SyncDelegateHost;
   private _files: {[path: string]: VirtualFileStats | null} = Object.create(null);
@@ -149,8 +189,8 @@ export class WebpackCompilerHost implements ts.CompilerHost {
     }
   }
 
-  private _setFileContent(fileName: Path, content: string) {
-    this._files[fileName] = new VirtualFileStats(fileName, content);
+  private _cacheFile(fileName: string, stats: VirtualFileStats) {
+    this._files[fileName] = stats;
 
     let p = dirname(fileName);
     while (p && !this._directories[p]) {
@@ -211,33 +251,48 @@ export class WebpackCompilerHost implements ts.CompilerHost {
   }
 
   readFile(fileName: string): string | undefined {
+    const stats = this.findVirtualFile(fileName);
+
+    return stats && stats.content;
+  }
+
+  readFileBuffer(fileName: string): Buffer | undefined {
+    const stats = this.findVirtualFile(fileName);
+    if (stats) {
+      const buffer = Buffer.from(stats.bufferContent);
+
+      return buffer;
+    }
+  }
+
+  private findVirtualFile(fileName: string): VirtualFileStats | undefined {
     const p = this.resolve(fileName);
 
     const stats = this._files[p];
-    if (!stats) {
-      try {
-        const result = virtualFs.fileBufferToString(this._syncHost.read(p));
-        if (result !== undefined) {
-          if (this._cache) {
-            this._setFileContent(p, result);
-          }
+    if (stats) {
+      return stats;
+    }
+
+    try {
+      const fileBuffer = this._syncHost.read(p);
+      if (fileBuffer) {
+        const stats = VirtualFileStats.createFromBuffer(p, fileBuffer);
+        if (this._cache) {
+          this._cacheFile(p, stats);
         }
 
-        return result;
-      } catch (e) {
-        return undefined;
+        return stats;
       }
+    } catch (e) {
+      return undefined;
     }
-
-    return stats.content;
   }
 
-  // Does not delegate, use with `fileExists/directoryExists()`.
-  stat(path: string): VirtualStats {
+  stat(path: string): VirtualStats | null {
     const p = this.resolve(path);
     const stats = this._files[p] || this._directories[p];
     if (!stats) {
-      throw new Error(`File not found: ${JSON.stringify(p)}`);
+      return this._syncHost.stat(p) as VirtualStats | null;
     }
 
     return stats;
@@ -345,7 +400,8 @@ export class WebpackCompilerHost implements ts.CompilerHost {
       _sourceFiles?: ReadonlyArray<ts.SourceFile>,
     ): void => {
       const p = this.resolve(fileName);
-      this._setFileContent(p, data);
+      const stats = VirtualFileStats.createFromString(p, data);
+      this._cacheFile(p, stats);
     };
   }
 
diff --git a/packages/ngtools/webpack/src/virtual_file_system_decorator.ts b/packages/ngtools/webpack/src/virtual_file_system_decorator.ts
index e7b4cb049f..205a87e2c3 100644
--- a/packages/ngtools/webpack/src/virtual_file_system_decorator.ts
+++ b/packages/ngtools/webpack/src/virtual_file_system_decorator.ts
@@ -18,17 +18,16 @@ export class VirtualFileSystemDecorator implements InputFileSystem {
     private _webpackCompilerHost: WebpackCompilerHost,
   ) { }
 
-  // We only need to intercept calls to individual files that are present in WebpackCompilerHost.
-  private _readFileSync(path: string): string | null {
-    if (this._webpackCompilerHost.fileExists(path, false)) {
-      return this._webpackCompilerHost.readFile(path) || null;
+  private _readFileSync(path: string): Buffer | null {
+    if (this._webpackCompilerHost.fileExists(path)) {
+      return this._webpackCompilerHost.readFileBuffer(path) || null;
     }
 
     return null;
   }
 
   private _statSync(path: string): Stats | null {
-    if (this._webpackCompilerHost.fileExists(path, false)) {
+    if (this._webpackCompilerHost.fileExists(path)) {
       return this._webpackCompilerHost.stat(path);
     }
 
@@ -52,7 +51,7 @@ export class VirtualFileSystemDecorator implements InputFileSystem {
     this._inputFileSystem.readdir(path, callback);
   }
 
-  readFile(path: string, callback: Callback<string>): void {
+  readFile(path: string, callback: Callback<string | Buffer>): void {
     const result = this._readFileSync(path);
     if (result) {
       callback(null, result);
@@ -79,7 +78,7 @@ export class VirtualFileSystemDecorator implements InputFileSystem {
     return this._inputFileSystem.readdirSync(path);
   }
 
-  readFileSync(path: string): string {
+  readFileSync(path: string): string | Buffer {
     const result = this._readFileSync(path);
 
     return result || this._inputFileSystem.readFileSync(path);
diff --git a/packages/ngtools/webpack/src/webpack.ts b/packages/ngtools/webpack/src/webpack.ts
index 660f39edf5..91169a791c 100644
--- a/packages/ngtools/webpack/src/webpack.ts
+++ b/packages/ngtools/webpack/src/webpack.ts
@@ -51,13 +51,13 @@ export interface NormalModuleFactoryRequest {
 export interface InputFileSystem {
   stat(path: string, callback: Callback<Stats>): void;
   readdir(path: string, callback: Callback<string[]>): void;
-  readFile(path: string, callback: Callback<string>): void;
+  readFile(path: string, callback: Callback<string | Buffer>): void;
   // tslint:disable-next-line:no-any
   readJson(path: string, callback: Callback<any>): void;
   readlink(path: string, callback: Callback<string>): void;
   statSync(path: string): Stats;
   readdirSync(path: string): string[];
-  readFileSync(path: string): string;
+  readFileSync(path: string): string | Buffer;
   // tslint:disable-next-line:no-any
   readJsonSync(path: string): any;
   readlinkSync(path: string): string;